Because they believe in perfection, to the point of wanting to "perfect" the whole galaxy (if not the universe) so they want to assimilate other cultures in order to do this (cloning wouldn't accomplish this.) Voyager fucked this idea up, much like they fucked a lot of things up, but I had the theory that the Federation was the reason why the Borg went from simply being machine-like beings whom Guinan suggested it was possible to reason/align with to the assimilators we see through the rest of the time we see them. The Borg are, pretty much, the "anti-Federation." Before encountering the -D in System J-12 they were just a race that adapted machinery with biology and they did the same with the 12 they took from the -D. Well, when they began aquiring the minds and thought patterns of those 12 they got the ideals of the Federation (galactic unification) and took it to a twisted extreme. Kind of the way some may look at the Federation and how they "assimilate" races and neutralize them into "one race." So the Federation is, indirectly, why the Borg started assimilating. See? Perfect. Fucking Voyager.
The Borg use genetic engineering--the nanoprobes' assimilation process rewrites victims' DNA to match Borg genetic patterns. As for cloning, maybe the Borg see the same problem with replicative fading. While they do seemingly clone the Queen, perhaps they find it more efficient to simply plunder the galaxy of available resources -- fresh bodies instead of expending the energy to clone. Finally, assimilation offers the benefits of new individual knowledge and cultures...something that a clone cannot do. A clone is more of the same.
Eh, while VOY was not perfect with the Borg I've seen nothing to suggest the Borg weren't already assimilating by the time of "Q Who?" The Borg Queen certainly supported this assumption in FC, and given how long the Collective has been around (thousands of centuries, according to Guinan), I think the most the D could have offered them was a new target.
Granted that we lack evidence either way, on most aspects of the argument. Take the cloning of Queens: both the Thompson and Krige models have appeared, died, and appeared again. So either the Borg clone the bodies of satisfactory Species 129 individuals whenever they need a curvaceous Queen - or then this Species 129 features only a limited number of phenotypes that naturally repeat (like the Benzites seem to, as per "A Matter of Honor"). It may also be that the various Kriges do not actually look anything alike: only the heads, which are artificial through and through, are identical. And yes, the Borg might have been their VOY selves all along, including before and during "Q Who?". They do have different mission profiles on different occasions; not every sortie would involve kidnapping Captain Picard and assimilating his crew. Finally, any abnormal Borg encountered may be just that. VOY suggests the Borg are secretive; so if our heroes ever actually encounter some Borg, these may be damaged or otherwise aberrant individuals who do not quite represent the mainstream Collective and its wish for secrecy. Timo Saloniemi
"Q Who?" specificly suggests they were only interested in technology. They didn't start asimilating until BoBW, after they met the -D.
Even more specifically, the God of Lies in "Q Who?" suggests the Borg are only interested in technology. And even if Q was being serious for that rare once, his comment about the Borg interests need only apply on that single moment in time. The Borg there could have been sated with assimilating the J-25ians, and would only have mild curiosity towards the E-D. Certainly we can't take Q's comments or Riker's observations and interpretations of the Borg as authoritative in any way. Even Guinan's insinuations may be colored by her hatred. This is the first time our heroes meet this radically different species, after all - they are bound to get a good number of misconceptions that won't be sorted out until much later. Even without "reimaging" TNG in any way, we could say the Borg there were always the same as in VOY. They assimilate Picard by sticking a tubule in his neck, at which point his skin color changes. They could have done the very thing to Riker, Worf or Crusher if they had reached hand-to-hand range - but they didn't, except with Data who couldn't be injected, and Worf, who managed to grab the Drone's arm long enough to prevent the tubules from piercing... Timo Saloniemi
Even without nanoprobe DNA adjustmant the "borging" process seems to negate most advantages you'd get from genetic engineering. And it doesn't seem like shortage of manpower is a problem for the borg. I mean they assimilate whole civilian populations. They're probably limited by dilithium deposits or some other unreplicable material.
True, but "technology" doesn't necessarily mean only mechanical technology. From the Borg perspective, humanoids are probably just another form of technology - living tech. So I don't see a conflict between Q's statement (assuming it's true - I tend to think it is because of his preference for smugness) and the assimilation process. It's not unlike how the Shadows used telepaths as sentient "cores" for their ships in B5.
Just as a side note... the first time we saw the "Borg Baby" in Q-Who, I assumed that the baby we saw was not a captured and then assimilated baby, but rather was a "native" Borg infant. And I doubt that Borg have sex, so I assumed that this baby was conceived in-vitro and "grown" in an incubator. The only issue, really, is "is the baby a clone" or is it a new genetic combination of two (or more?) sets of DNA available? See, that's not "cloning." But I suspect that it's very much "the way of the Borg."
That's pretty much how I see what happened in "Q Who", too, with regards to the baby we see. Not a clone, but a genetically engineered offspring. They might well do that because of the aforementioned genetic problems inherint in the replicative fading. This could be a "work around" for that problem, taking eggs from a suitable female and sperm from a suitable male would quite possibly give you something close to a cloning process - "organic cloning"? - each time you processed the inception. The only thing you would likely have to worry about is mutation in the early stages of the growth period. Of course, you'd be limited in the number of potential clones I don't know that I'd call those early comments misconceptions, exactly. While certainly colored by the individuals viewpoints, they all seemed to be dead-on from what we saw on-screen. Even Q's comments seemed to back up what Guinan said with regards to the Borg. I also agree that they've likely been very much as we saw in them from both TNG thru VOY, w/the "variations" being more a matter of mission directive than anything. Of course, I didn't watch the last season-and-a-half of VOY, so don't know what else was revealed. The only episode I saw from season 7 was the last one, and I was mostly disinterested in it after the first 20 minutes or so, having already figured out the plot and how the series would be most likely to end. Worf the Bad Assed Klingon! I imagine he'd find a way to take himself and a dozen Borg out if they managed to actually stick the nanoprobes in him.
Seven tells us in One that the Borg do not create their own children (or at least that was my understanding) The children spend their time in a maturation chamber until they are fully grown
That's an interesting point. However, one could cry "RetCon" on the part of the VOY episode w/regards to what Seven said. Regardless, you could easily put a newly born artificially incepted Borg child in a maturation chamber. I'm sure they were looking for more of the horror angle, tho. Imagine what it must be like to be a newborn, toddler or even preschool child that is assimilated by the Borg. To me, that's even worse than being an adult and being assimiltated!
Remember we're talking about a TV series here. Which means any information given to us by a character we have to take as gospel because it is the only information we have to go on. There's no otherway to expositly deliver the information that the Borg are only interested in technology than to have Q and/or Quinan tell us. We have to take their word for it. So either the writers for Q-Who knew what they were going to do for an episode that wouldn't be written for another year and a half and had Q lie about the Borg or they simply changed their minds for story purposes on how the Borg worked. I personaly believe the second one and reconcile it by saying that the encoutner with the Federation changed the Borg into an asimilating culture (exactly what the Federation does). Which has a nice poetic symetry to it. Unfortuantly Voyager's PTB didn't have any sense of this dramatic irony and either completely ignored it or it never dawned on them.
... or that was never the intention from TNG and that same lack of intention lent itself to VOY deciding their own course. You also need to remember that however many years passed - both in the Real World and in the TNG/DS9/VOY universe - and that the Borgs agenda changed, as well. Especially when you throw Species 8472 in to the mix.