I apologize in advance if this seems more like a rant.
You see it all the time when you are gaming. "What do you want to play?" "Lets play super heroes!" "Ok, I'll set it up". Only when you are actually in the game, the players aren't playing super heroes. They're playing Super powered PCs. They don't take risks, they always approach with the most careful of war game strategies, and they always check twice before leaping anywhere. Now, don't go and think that all of this falls on the Players either, GMs do it too. Setting up situations that encourage that kind of play, or worse, that penalize not playing like that. Before you know it you have a game that isn't about Super Heroes, it's a chess match between the players and the NPCs, just instead of shooting guns or moving on a checkered board, the characters throw cars and shoot lasers out of their eyes.
Don't get me wrong, if that is how you have fun then there is nothing wrong with it. It just seems to me that when you mentioned you wanted to play in a Super Heroes game, that you were saying that you wanted to be in a game about Super Heroes. And to be honest, I don't remember the last time I was reading a Super Hero comic and watched as Superman snuck up behind the bank robbers to take them out stealthily one by one. I do remember seeing a lot of him kicking in the front door and letting bullets bounce harmlessly off of his chest before taking out the robbers. The hostages don't get killed when Superman shows up, its just not how the genre works.
Heck, even non-powered characters like Batman do the just walk right up angle. Sure, Batman will show up by sneaking in and taking out one or two guys. But usually it ends with him slowly stalking towards a terrified individual, completely in control of the situation as he goes along. Again, it is just how that genre works.
As the GM it is your job to set up the world to match the genre. If you're running an Epic War story, you are responsible for providing an environment where the epic can happen. If it is a Space Opera, you need to provide what is needed for that. If you keep running based off of realism, when doing settings and genre that are so far from realistic you can barely even see reality you are doing a disservice to the genre. You are not telling stories for that genre, because the points of conflict are handled differently.
As the player it is your job to play up to the world and the genre. If you are playing Super Heroes, than act heroic, just waltz right in and solve the problem with gusto and style. If you are doing an Epic fantasy war story, then call someone out to a personal duel Achilles style just to make sure that they die by your hand. Play to the genre and let the GM know that that is what you want to do. If you don't, if you keep playing it like a strategy game where there is only one right answer, don't be surprised when the GM starts playing that game out of the assumption that it is what you want. Mistakes are fine, they make for fun things to deal with, and unless your GM can't be trusted they're not going to just slam you for one little mistake.
Again, there is absolutely nothing wrong with playing the game any way you want, if that is how you want and people are having fun doing it. However, this 'ultra realistic and cautious' approach in games I've seen tends to come from an adversarial approach between the players and the GM. A game in which the players are hyper-cautious because they don't want to mess up and bring down the fires of failure upon them. If that is your cup of tea, by all means enjoy. However, I prefer the cooperative relationship. The GM and players telling a story, trying to have fun together. In that kind of a game you shouldn't need to fear the fires of failure. You should be able to play it up, have fun. The GM should be able to trust the players to act in character and play to how the world is set up. The players should be able to trust the GM to not suddenly change the rules of the world and slam them down for trying to play into the game.
So, if you say you want to play super heroes then play super heroes. Not super powered thugs, or super powered strategy game pieces, but actual super heroes. Have fun with it and, as usual, remember: