That's why you also have to train licking olive oil off guys' bodies.
I'm not sure but I have noticed if I train sub-wrestling for any length of time it can hurt my gi-game in some aspects.
I think a lot a mma fighters who came from gi sports (judo, bjj, sombo) would have a hard time going back to those sports and be succussful at the elite level. Guys like Nakamura, Sperry, Bustamante, etc. may not be able to transition back to their previous sport as well. They've been fighting without the gi for too long now and their opponents may have surpassed them with the gi. This may be why many jujitsu guys are hesistant to always train no-gi, as if that were more honorable or something.
1) I think this gi vs. no gi thing is as ghey as bjj vs. judo.
2) I think that for the most part a gi base can def. help a no gi game but that if you are primarily a MMA guy, you do also have to train no gi a lot too, dont ya?
3) I think it depends on the fighters too, every fighter is diff. and have diff. styles.
4) One comment on the "yeah but you dont walk around the street with just shorts..." Thats true but a t-shirt (which is what you'll normally be fighting in) is def. not as solid to grip as an actual gi, right?
Just some thoughts...
"All the leverage points are the same. Instead of grabbing the collar, you grab the back of the neck. Instead of grabbing the sleeve, you grab the wrist, or behind the elbow. Instead of grabbing the pants leg, you grab the calf, or behind the ankle, and so on."
The leverage points can be the same most of the time but we all know the amount of leverage, torque, momentum you get from pulling or gripping with a gi is no comparison to without.
I love the gi.
I think no-gi is a little easier. And I'm mostly a gi player, I only do no-gi for extra matchs at tournaments, and often don't do much no-gi training, yet I still do ok/win at tournaments.
The main thing no-si is that sweat makes everything slippery. I find people can slip out of stuff that with the gi, I would have had a lot tighter. I also like tie ups, which don't exist no gi.
The gi gives people extra handles, so I have to stay tight, really tight, passing the guard for example. No gi I can be a little 'more sloppy' as it were.
Summation: going from gi to no-gi is fairly easy. Going from no-gi to gi is fairly hard. Collar chokes and tie ups alone often put no-gi people off their game. The reverse doesn't seem to hold true as much. As always doing both is best, as they both have something to offer. Personally I just think the gi is LOT more fun to study/train/fight.