Now if you're running that old school "death is cheap" style of game, well, none of this matters. Death lurks around every corner, and a TPK isn't a "fail state" for the campaign.
However, 5e wasn't designed to have games exclusively follow this model. From the PHB:
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If this sort of game is considered to be the "default" by the designers and is their starting point, then while having individual characters die might not be a fail state, a TPK could be seen as such, and thus, ought be vanishingly rare. In that case, perhaps the system's "7ish encounters" isn't actually intended to completely drain the party's resources at all, but instead, always leave the party at a level with resources to spare, to give less experienced DM's more wiggle room when the rules for encounter building fail them!
After all, one can always use more encounters or flip levers and twist dials to make the game harder, if that's the experience you want- but that's certainly not something every DM knows how to do with finesse! I've been game mastering for decades, and I still haven't mastered it!
So things like plentiful healing and generous recharge rules aren't a bug at all, but a feature of 5e. Players generally winning most of the time and not dying is the intended play loop, and to argue that it isn't is simply ignoring the facts.
If you don't want this in your game, you have to change it. WotC isn't "Anti-DM", as the DM certainly has the power to enforce any sort of rulings they wish (subject to the breaking point of your player's endurance). It's default mode is simply not to some people's tastes, but that's ok as long as you recognize this fact and take steps to do something about it. 5e is fairly easy to kitbash (perhaps too much so).
Now if you don't want to go to that effort, or you think your players will balk at it, that's certainly a problem, but not one 5e is really designed to solve (but here's hoping the new DMG will address this in more detail).
The change to healing has nothing to do with game balance- balancing the game is, at best, a secondary concern for the designers (as far as I can tell). It's about providing an experience where choosing to use healing magic feels more like a valid option. Because looking at 5e, it has many inferior options to choose from. Some things are just better than other things. If a choice is bad, you learn not to take that choice, you find ways to stubbornly optimize that choice anyways, or you ask your DM to fix it.
I don't, personally, think that's a great way to make a game, but nobody asked me to make D&D, lol. It's merely the game as it exists. All that's happened here is that healing is a better choice than it was.
It remains to be seen if that makes it a
good choice.