I agree with GdD that sliding well can be accomplished with even a very thin crust loaded with toppings, as long as you have something it can slide on. Semolina does seem ideally suited to this.
Stretching very thin can, however, make the dough more likely to stick just because as you stretch, you often expose more of the interior moisture of the dough to the bottom surface, meaning it's more likely to get sticky. (This is particularly true of high hydration dough, but it's a factor even in drier doughs.) Also, when sliding off a very thin dough with lots of toppings, you risk tearing and/or bunching up the dough if you don't unload at an even pace.
To counteract the problems of sticky dough, I'd advocate shaking the peel periodically while adding toppings. If you keep the dough moving, you'll need a smaller amount of semolina/cornmeal/flour since any place where this barrier of dry stuff is thin will get moved around by the shaking. When I deal with wet doughs, I'll shake the peel at least once after every topping addition and often more frequently. (The only downside to this is that your dough will "spring back" a bit when you shake, so you'll need to stretch a bit more than you expect at first.) If you see an area of the dough that isn't moving, it also allows you to correct it early, before it "gets more stuck" and probably while you have fewer toppings and weight, making it easier to get under the dough and free it.
In any case, regarding Neapolitan style pizza, the center of the dough is often stretched so thin that it is quite translucent. As long as you have adequate semolina/cornmeal/flour to "lubricate" the peel, there's no reason to stop stretching unless you prefer a thicker crust or are afraid of tearing.
