I understand what you're saying. 50MP is more than most need or even can utilize. But dedicated focus assist lamp, wifi and GPS, among other advancements, to me is not worth noting. I never need wifi or gps, and I rarely need a dedicated focus assist lamp. If I don't want to use the pop up flash for focus assist, then I just mount the hot shoe flash and let it do focus assist. Surely, two of the most useless features on any camera are GPS and WIFI. What a waste of time and engineering. (please note the over exaggeration) The a77 had focus assist and gps. So what. The a77ii doesn't, but it does have wifi. So what. They both have af in video mode. Now that's a feature I can appreciate. It's one of the reasons I purchased the a77ii. My a580 has Focus Check Live and my a77ii has zoom focus. There are many people who don't use those features. That's fine. I don't want them saying that it shouldn't be on the camera and so I won't be suggesting that camera companies quit wasting time with wifi and gps. And for the same reason, I won't interfere with the MP race. Various features come and go. I remember years and years ago a canon my friend had. Keep in mind this was back in the film days. It had some kind of eye control focus mechanism. I have no idea how it worked except that whatever I looked at came into focus. Now that would be a real neat feature I think. Maybe it didn't work that well I don't know. Where did that tech go? Is it still in use by Canon? I don't know. I know I've never owned a camera with it. I'm not trying to be disagreeable. I'm just offering up what I feel is a somewhat balanced view of camera features (with a little sarcasm). Features come and features go. Most features get improved upon and stay until they are no longer selling points. Some brands tend to introduce, drop and reintroduce features. Others don't change quickly enough.
As far as the a99 successor goes, what features did you have in mind? I really am not up on its capabilities or any other FF for that matter. What do you feel Sony needs to put on it to make it competitive from your viewpoint? You stated that you would like to have varying sizes of raw available. What else would tempt you?
Besides, down road a few years, people that never shot a 10mp camera or perhaps had but forgot, will say, "24mp is enough, why do we have 100mp cameras? All they do is waste my hdd space and most people's lenses are only good to 50mp anyways." At least that's my prediction, because that's they way it always has been.