I believe I was one of the first to mention positionals, reason being, you can keep track of when you need positionals by knowing where you are in the combo just from what separate buttons you have been pressing. You know what your next GCD is once you press hotkey 'A' and that it needs Y positional, so you can plan. By consolidating buttons, you lose that way of tracking where you are in your combo.

Now, I never used it as an excuse as to have button consolidation in or not (in fact, IIRC, I mentioned having it in as an option) it was just something to consider as to why button consolidation is not always better and it is more of a case by case basis based on the player.