To be fair, despite the fact the D.Q species are more ragtag... it doesn't mean they couldn't co-exist in a United Federation of Planets.
Even the 3 founding species of UFP in the A.Q. were pretty hostile to each other (Vulcans, Andorians and Tellarites) until Humanity showed up and started bridging differences between cultures.
In essence, Earth had to undergo those massive socio-economic and cultural changes right after First Contact (an almost Resource Based Economy emeregent civilisation) so they could help create the Federation using cooperation, sharing, compassion, etc. as the baselines - plus Humans were new to the scene so they had no specific allegiances with anyone - heck even the Vulcans were 'just there' back then and didn't really share technology or crucial knowledge with Earth.
In that sense, I don't see why a D.Q. UFP would be impossible - eventually.
Voyager had a bad start with species that covered more space vs species that had a planet and a few colonies (such as the Talaxians).
In the case of the Kazon, this was more or less unavoidable, plus with VOY destroying the Array had that first Maje start spreading bad rumors about VOY which made their journey in the first couple of years more problematic.
Janeway could have specifically worked with the Kazon to help them build sustainable water generation facilities without sharing replicator technology (its more than doable with even 20th century technology, which actually baffles me as to how did the Kazon and other species managed to end up with massive water scarcity given that ice asteroid are fairly common... unless the Caretaker's meddling with the Ocampa planet had wider reaching implications in that section of the D.Q. (but it was suggested their meddling was contained to the planet, not that part of space).
There were also the Vidiians - but that wasn't VOY's fault.
Had Voyager managed to help the Vidiians find a cure for the Phage in the first 2 years (for which the Doctor could have used B'Lana's DNA), things may have gone down differently. The Vidiians had a large part of space and plenty of powerful ships at their disposal. I'd think they would have made a good candidate for a starter UFP species (after the Phage has been cured) along with the Talaxians who could take refuge in their part of space.
The relationship between the Talaxians and Haakonians was bad to say the least. What if VOY helped mediate diplomatic talks between the two and Neelix coming into his role as an ambassador because of that instead?
The Vidiians DID end up curing the Phage thanks to the Think Thank though... so they would probably be more friendly now towards other alien species, and who knows, perhaps try to mend some broken fences with other species whom they previously hunted for organs - though to be fair, now tha the Vidiians are no longer hunting other species for organs, the previously antagonized alien species could try hunting them instead as a form of retribution.
Some alliances could form as a result of Voyager's early travel through the D.Q... would depend on the willingness of other species to do the same.
And while we don't know what kind of technology Janeway may have shared with the 37's and their descendants... probably very little to none as they seemed to have been fairly self sufficient and well off on their own... but may have provided some hints on how to build starships.
