Edit: As far as "optimizing the fun out of a game" goes, I *really* disagree that is the case here. Part of the *fun* of a game is trying to figure out what the optimal choices are in any given situation. If the optimal choice keeps on being "caste haste", you've made a boring game. "Using a spell that you have access to in the normal course of play" is hardly some obscure, arcane strategy arrived at by people straining to be as optimal as possible.
Sure, it is fun to figure it out. And when you have your sorcerer that shoots lightning bolts in every direction and wipes out an entire room of high hp enemies, you've done that. And you had fun. That's good. You haven't optimized the fun out of the game.
But, if subsequently, that is all you ever do, and due to that, you are now not having fun, now you are at a point where you have optimized the fun out of the game. And this gets even worse when you get the people who fall into the "If it isn't the best, it is garbage" mindset, and who will set out to try and force everyone else to play the way they do. This is a single player game. That means two things. The first, the single player bit, means that you can play however you want, and it won't ruin the game for anyone else (unless you're one of those munchkins I just mentioned). The second is that it is a game. Something those of us who are not content creators do for fun. If you are not having fun, either change how you play or go do something you do find fun. Heck, go find other optimal ways to play.
"Doctor, it hurts when I do this."
"Well, don't do that."
When it comes to a game, that's good advice.
And note that I'm not saying Haste is balanced. I've already said it isn't. But if you have the slightest bit of willpower, you can just not use it. Nobody is aiming a hand crossbow at your head from 18m away, forcing you to.
