The thought that the two (Drizzt and the rule change in 2e) were connected never crossed my mind at the time. I read the books first and just assumed that if there was a justification for Drizzt TWF'ing, it was because he was a Drow. I say if because by two weapon fighting rules of the time, a regular player couldn't use two scimitars - a scimitar was too big to be an offhand weapon.
When I later read the 2e PHB I assumed the ranger TWF change was for two reasons. The first was to give them a little more oomph in combat because Fighters were getting specialization. But I also saw it as an incentive to players to go along with what seemed like a recasting of what a Ranger was.
In the Greyhawk Adventures book, Duke Karll of Urnst is a 12th level Ranger, who appears to run around in Full Plate +4. And really, why wouldn't he? There was no reason not to wear the heaviest armor possible to give you the best AC.
But 2e tried to change that. Right off the bat, adding abilities to hide and move silently signified a shift in the archetype from Deluxe Fighter (because, like Paladins, we're simply better (statted) than you) to a more woodsy, skirmisher type - you know, like a Ranger
Two weapons had always been a good way to increase damage but it needed (or at least I thought at the time) that it required a high dex to make it work - a high dex that you usually didn't have as a fighter type having Str and Con as higher priorities. That change was a good incentive to get my ranger into studded leather - two weapons, heck ya that's cool!
And a final thought, is there any chance that Drizzt uses two weapons *because* they were planning to give it to Rangers in the new edition?