I think most people are not "bitching about an unfinished product" but moreso being dissapointed/annoyed at getting something rather different than what was promised (A game that resembles 5e closely).
If you order a medium-rare steak and you get a well done one, for the same price, you'd be rather annoyed, I figure.
An unfinished game that's mechanics will be in flux until it's out of EA. If I went to a restaurant where I could pay for all you can eat steak while they train new cooks or try out new things on the menu I would expect certain things not to be the way I want them. If you have in your mind what you wanted and won't be happy unless it's exactly that thing, you should have waited until the game was out of EA and reviewed to make sure it was that thing.