I KINDA get where you're coming from; I've played GG on pad since the beginning and I've gotten to the point where I don't need to use a stick, since I can use the characters I want to play without any real execution barriers (except for my own ineptitude); but years until you're half way decent on stick? I dunno about that. I started playing MvC3 on a PS3 pad from when the game came out till like September. I've been playing the game on stick since then and I'd already say I'm better on stick then I am on pad.
Just saying; it won't take nearly as long to learn stick as you think it will and it really does help for these newer games that are cross-platform. GG is on PS2 and always will be on PS2 so I have no real reason to switch to stick.
...in other news, coal-powered sex piston.