Well I hope the rumors aren't true BUT I can see two sides to this story.
I think Disney is probably thinking more about customer satisfaction here, and less about profits. I could be wrong but let me explain my thinking. I don't know how much extra profit they could make by doing this. I mean we are a captive audience, we
have to eat somewhere lol. Even if it gets people out the door quicker, the same number of people still have to eat at some point, right? Especially if they are on the dining plan. They are pushing the dining plans so hard and giving it away for free as well, it's not like they are going to lose money on those people, they've already paid for the food so they're going to find somewhere to eat. People will either wait or go to another CS I would think. If someone is going to leave the park to find somewhere to eat, chances are they would have done that anyways. If it's about profits, it's probably more about getting people out the door to spend their money elsewhere in Disney, rather than the profits of the actual restaurant IMO.
I think getting people out the door quicker would help customer satisfaction. I had a hard time finding a place to sit at several places on our trip last year. Some people were just sitting in the air conditioning and resting and not even ordering anything, or just a soda. Or maybe they had already ate and were just hanging out longer. That was frustrating since I was standing there holding a tray of food getting cold lol. So honestly if it deters people from doing that or getting out the door quicker I'm all for it. Yeah I'd prefer to have chairs with backs, but I can see their point.
Another thing to consider is the plus size crowd. When those chairs with backs have the "wrap around" or curved style back, sometimes larger people just can't sit in them. Trust me I know, and I'm not even that big. So I think stools would help in that aspect, and at least they're padded. At least they are at Pecos Bills.
As for young children, I assume they are going to keep the rolling high chairs so that should work for them. I do feel badly for those that NEED the chair backs. I am assuming Disney would keep some "real chairs" that you could request, how could they not? And some places do have some booths, hopefully they'll at least keep those. (And hopefully you won't have to make ADR's for them!

)
The bottom line is, I hope the pros out-weight the cons with the stools. Pecos Bills was usually busy on our trip last year, they had stools then, so the stools don't seem to be bothering people enough to stay away from there. OH and I did find an interesting pic from Pecos Bills circa 1985... look, stools! lol And omg they look way less comfortable that the ones now.