Yep, I really loved my Buick LeSabre, but I know what you mean. People are so resistant to change! I am so in favor of getting rid of fixed dining times, but it was not clear to me whether or not this change accomplishes that.
On the other hand, I don't want to have to pre book everything. The cruiselines, including NCL with their freestyle dining, do encourage that, because to know how many are dining in each venue makes their planning so much easier. The reality for NCL, and my guess is for RCCL as well, is that most people have no interest in reserving far in advance, and some will do it the day of, and most will just wing it and walk up, if that is allowed.
Comparing it to NCL's concept, if my understanding of how RCCLs will work is correct, NCL has retained their big MDR, with live music and fairly casual dress, while RCCL eliminates theirs and replaces it with 5 small venues. These venues will differ in theme/decor and menus, but the menus will remain fixed daily. NCL 's three MDR venues have one fixed side, and the other side changes daily.
I think it's a step in the right direction for RCCL, but it will be interesting to see if their cruise prices go up to cover these changes. I would have to really like the itinerary in order to make me book their already higher fares.