RAMA
About the borg 'changing':
Picard's words said it best, in 'Scorpion' - "You should not expect reason or compassion from the borg. In its collective stare, it knows no reason, no remorse; only the will to conquer."
The borg is a special case - a sentient mind, without free will; the hive mind follows static, unchanging impuses/drives.
That's why the borg is situated the boundary between sentience and non-sentiece. And make no mistake, there is nothing unstable about its state, nothing amenable to change, to 'evolution' as you call it - its motivation didn't change since its appearance -
'the will to conquer'.
When dealing with the romulans, Dominion, etc, there is always the chance they will choose to have peace.
NOT so with the borg - peace is trully not in its nature, just as it isn't in the nature of a calculator to paint.
You praying for the borg to change is a waste of time - you might just as well pray for the souls of your ancestors to come back from the dead as you remember them and start talking about what's new.
About the Federation inventing some magic gizmo to turn the borg into angels:
Your argument has become that Picard was right not to use the paradox in 'I, Borg' because the Federation will invent a magic solution that can do whatever you want.
Your magic solution is
RIDICULOUSLY IMPROBABLE, RAMA! The chances of it coming to pass are so low, I doubt one can calculate them, even mathematically

!
RAMA, the borg has assimilated THOUSANDS of starfaring species - at least. Don't you think that, if it was so easy to stop, it would have been stopped long ago?
The paradox virus from 'I, Borg', with its high chances of success against the borg (Picard&crew were certain it would work in 'I, Borg"), was better than anyone could realistically/reasonably hope for!
The Federation couldn't have found a better weapon no matter how long it would have searched. That paradox was a godsend! Thousands upon thousands of advanced, assimilated species stand testimony to that.
Waiting to find something bettrer is not only idiotic, but also suicidal (for your people) and criminal (for the BILLIONS Picard let die).
About the so-called Federation Borg war you mentioned:
RAMA, do you actually think that, if the borg would send - let's say 1000 cubes (by its standards, a small force) - the Federation could actually face it in war to a stalemate and then make peace

with it?
1000 cubes vs the Federation woldn't be a war - it would be a massacre! I doubt Starfleet would survive 2 weeks (and these only because the cubes need the time to reach starfllet's fleets).
1000 cubes vs the federation/the romulans/the klingons united will still be a massacre (but hey, now it will take take a whole month for the borg to wipe the alphans out

).
That's the disparity in power between the federation and the borg!
As for the borg making peace - well, good luck with those prayers of yours

.