It is not unknown for console games to be converted to PC with a fair amount of success. Unfortunately, the reverse is not true. Command & conquer, DooM, Quake - all were converted from PC to console, and none of them were worth playing in their console incarnations.
Also, Bg1 is ancient now, and BG is quite old as well. There is no official development on any of the BG series. If they were going to do the conversion theyd have started by now.
So I doubt that BG will be appearing on PS2 in any form much improved over BG
ark Alliance. Stick with the PC version.