i just bought dragon age origins, and its a cool game but my computer struggles to run it, and it gets kind of sluggish so im wonder, why havent we seen baldurs gate or planescape torment on GoG? id like to try em out!

Considering that Planescape: Torment, Baldur's Gate series and Icewind Dale series are being rereleased on 13th of november, I don't think there's that much of problem with licenses (do remember that both BG and IWD series were already rereleased worldwide by ATARI few years back). More than likely there just have not been that much interest at ATARI for making another rerelease.
Also GOG has not yet managed to persuade ATARI to offer their titles in GOG.com. Until that happens we won't be seeing any ATARI games here.

http://www.gog.com/en/forum/general/whoohoo_i_just_found_a_nice_surprise_in_my_garage/25
maybe you have a copy of it in your garage like I did!!!

I'm sure GOG would be working their arses off trying to get the likes of Baldur's Gate, Planescape: Torment and so on. They're massively talked about games, and would more than likely attract even more people.
That being said, you'd have to go through the distributors, face what would be increasing competetion for the titles, and since they're being rereleased, it's obvious that the distributors want to milk as much money out of the franchises as possible.. By being bastards and selling them for more money than GOG would.
But that's just theory.

I hope GOG keeps trying as the more units sold through GOG the better they look to sell other companies games.

The main issue is getting Atari on GOG and WotC to okay their sale from a digital distribution platform.

No, it will never be here.