There were some other things brought up in this thread, which I'll address:
1) The Borg didn't kill anyone from that world they assimilated in BOBW. The wording was that they "scooped" everything off the planet. The away team beams down there and we see a giant hole where a city was. So what dead bodies are you (Zar) talking about?
You're right there were no bodies, but then again Guinan didn't say there were bodies either, she said there was "little or nothing left". This was the first clear hint in BOBW that it was in fact the coming attack that Guinan predicted. In QH they merely scoop out part of the Enterprise's hull, for "information gathering". In the real attack they scoop up an entire planet at once, just like Guinan said happened to her people.
And by the way your first hotlink doesn't work... here it is on tinypic: http://i51.tinypic.com/fkzf40.jpg
Both links work for me, but thanks.
Yet they still have to figure out the shield & phaser frequency every time?
Hasn't the tech of the Federation been developing for thousands of years too?
Are the Borg just a mirror of us, if we allowed tech to overrun us? Isn't that why Picard & Janeway both keep talking about that's why individuality is better than the hive mind? Isn't that why we keep finding loop holes in their "superior" technology because they don't think of everything?
Didn't Guinan also mention the more the Federation got used to the Borg, we might be able to learn how to deal with them?
So it was planned back then that we'd be able to be somewhat equal in time.
Starfleet alternates their shield and phaser frequencies, when fighting the Borg. This was stated on screen. There's no way that we could ever be equal to the Borg. It just doesn't work that way. It's like saying that one day, we're going to make germs go away. No, we're not. It just doesn't work that way.
The reason they kept finding loopholes is because the writers decided that they should find loopholes. Nothing more.
It isn't writer incompetence.
As a writer and producer, why would you sabotage the future of the Trek universe and you're own job by assimilating Earth and ending any future of Trek?
So again going by what Guinan said, one day the Federation would and can get around the Borg. The writers were following their own canon the whole time.
Well, whatta you know, I'm a writer, too. Small world/big Internet. They didn't have to sabotage anything. When creating an enemy that's outrageously overpowered, the best thing to do is (a) keep their appearances to a minimum and (b) all encounters with them must lead to HEAVY repercussions/casualties. Anything less than this is incompetence.
It happened with Doomsday. It happened with Venom. And it happened with the Borg.