I'm not 100% sure what you mean by "satisfaction on the 'gameplay' level" - which seems to invovle a lot more than just character building - but as far as PC building is concerned I think my players care as much about finding options that better express their PCs as finding options that "min/max".
Sure. And if player want options to express their PCs and the system either alters or excludes those options because they are perceived to be unequal to others, that player is going to be pretty disappointed. Moreover, if I as a DM am trying to push the characters, challenge them in some way, and I can't because they're equally useful in all situations, it makes my job harder.
I've seen variations on those problems a lot more than I've seen anyone complain that their character options were over/underpowered.
But I also think it's important to point out that the charop forums, builds, and min/maxing are important parts of the game, and that a true parity of all options presumes that they aren't and renders them a waste of time.
Or, to phrase it another way, the idea that system mastery should not be a factor is equivalent to taking skill out of the game. A truly balanced game, in this paradigm some people are putting forth, would be Chutes and Ladders. You make no relevant choices and the outcome is completely random. Replace that with a d20, call it an rpg, and you can narrate the outcome however you like. Not the game I want to run though. I much prefer to look at the "game" aspect of D&D as a game of skill, in which selecting some options will lead to better or worse outcomes than others, in a somewhat but not completely predictable fashion.