It was hyperbole to express how silly the concept was. Sorry you've taken it literally.
DRG is heavily rigid, yes. That said, True Thrust is the jumping off point for 2 different chains. Your current example is impossible due to this. In addition, it's entirely missing Raiden Thrust. Perhaps you've not played it in a while?
Regardless, there are instances beyond the most rigid rotation in the game, such as SAM. Hakaze as the starting point allows you to enter into 3 different combos, each doing something different. This allows for one to make snap decisions, such as going to Yuki early to take up your filler GCDs, or altering the overall flow on the fly to better work with the situation, or even just Ad Hok SAM in general. With a 1-2-3 system, this becomes impossible. Or do you propose players keep 3 separate instances of Hakaze on their bar? Or that, in order for your "option" to work, you would basically need to switch SAM over to the current PvP-style GCDs. Not sure how happy all the SAM players will be to have Midare nerfed because you reach it 2 GCDs earlier every time.
But then I didn't think I'd need to spell out the ramifications for you.
