We don't talk about Pun-Pun
Well, the game is powered by nostalgia and "D&Disms" as much by anything else. Radical changes to the game have had mixed reception in the past. And some people are saying that a radical change is no longer in the cards for D&D.and wotc should absolutely be considering if including more HP like spellcasting is a worthy addition to the game. The fantasy experience will change over time, and any smart RPG system will need to consider adjusting with it.
I'd like to see an optional rules module or even a new class that would allow for this sort of spellcasting paradigm to exist, but I don't expect WotC to make such a thing- a lot of great new ideas that have been introduced in UA's have withered in the face of customer satisfaction ratings, so at a certain point, if the majority of your consumers aren't happy with new ideas, why spend time presenting them?