I disagree. The fact that you only have a limited number of daily/ encounter powers are more than enough encouragement to do stunts. After all, there will be combat left after you have used all those powers. Stunts do have to be better than At-will powers to be encouraged, that is all.
I agree. The thing I found was difficult about running 2e was that the ONLY attack you could make was just...attack. Because of that, people would either:
a) get bored and try "stunts"
b) try "stunts", not knowing there were no rules for them.
Then, the game slowed to a halt as I'd have to think about a rule that seemed balanced, finish the resulting argument about whether that rule was "realistic" enough, and eventually resolve the action.
The arguments pretty much always went like this:
Player: "I attempt to leap off the ledge an on to the Ogre's back and hold on to him."
DM: "Alright, make me a Dex check to see if you can grab on to the Ogre."
Player: "Dex check? But I have a 6 Dex. Shouldn't it be a Strength check? It's not like the Ogre is very small or anything. I can easily hit it, it's just a matter of holding on."
DM: "No, you need to first aim correctly while it is moving around and you are jumping, it requires a lot of coordination."
Player: "Then I don't want to try it."
DM: "Too bad, you said you were doing it, you don't know the chance of success before you try something."
Player: "Woo hoo, I rolled a 2, I made it by 4!"
DM: "Sure, you are holding on to its back, and it can't hit you since it can't reach back there. You'll need to make a Dex check to hold on every round, though. You can attack as normal."
Rogue Player: "So, if I succeed in a Dex check, I can grab on to the back of enemies and they can't hit me? And I can backstab them every round? I have an 18 Dex, that's awesome."
DM: "Umm, yeah...that's what I just ruled....mind you, I wasn't really thinking of an 18 Dex rogue doing it in every combat when I ruled that....maybe this wasn't such a good idea. I can't think of a better way of doing it. Sorry, I'm going to have to rule that the Ogre is moving around too much, it's just impossible to grab on to him."
Player: "Fine, I just attack him."
And that was one of the simple ones. If you got a couple of players who had a vested interest in making sure a new rule worked well for them, an argument could easily take 2-3 hours. I remember one argument where 4 people and the DM were out of their chairs demonstrating a stunt to prove to their DM that it wasn't impossible and the DM pointing out reasons they weren't doing it right for hours.