If you buy D&D Next it will be in large part because of what I like. The difference between you and me, though, is that I'm perfectly happy for other folks to have their fun if I also have mine. It's hard to imagine myself ever playing this "Battle Master" fighter. Not really what I like. But if another player at the table is playing it? No problem, be my guest.
It's not as simple as just someone sitting next to you playing something different. The way you have phrased your statement would be like having two tables where one is playing 4th edition while another table is playing 3rd/Pathfinder. The people playing 4th can have all the fun they want because that game is separate. But the problem here is they have thrown the two concepts together under one game which can sigificantly alter my attitude of the game. It would be like baking making dinner for everyone and loading it down with salt. If I don't like salt then I am screwed because I can't realistically pick out every tiny grain of salt there is. I don't play 4th edition because I think the mechanics are aweful and very gamist. I can't enjoy a game where I am playing my PC but the guy next to me in the same game is using the types of mechanics I hate. It spoils the whole game for me. I play in a lot of sanctioned events so I play with a lot of people I don't know and frankly, I don't care what their personal preference is. I am there for "my" enjoyment and to play the game using "my" hard earned money. If the game were free, then I wouldn't care one way or the other.