For my groups I seriously doubt this would be true. We played without any hit dice and just basic cleric healing. And I don't think they made 5e harder.
"We removed the small source of healing, but kept the big source, so I don't think much would change." Yeah...I agree with that. Hit dice are mostly pointless. Being forced to use
only hit dice would have been outright lethal for literally every party I've ever played in.
200% is patently ridiculous from a verisimilitude perspective. This is also why I rejected 4e.
I don't understand why. Healing surges are inherently more like actual healing than spells are. They literally represent your body's ability to preserve homeostasis, and the fact that those resources are
not always accessible to you. Yes, you can
potentially take that much damage. But if you take more than 100% too fast? You are going down and only the intervention of others can realistically save you. (Remember, in 4e, when you roll death saves,
that's per day, not per combat. You can only fail death saving throws two times
per day safely.)
My point is that I don't like the whole 4e notion of healing which in some ways carried forward into 5e. I'm never going to play that way. I agree though with you I wouldn't have unlimited healing wands like they did in 3e. That was not true in 1e, 2e.
Again, I don't understand why it's a problem. This is literally, actually more like real human response to injury:
if you can prevent the patient going into shock, you can usually save them, even from extremely serious wounds (we're talking limb-blown-off wounds here, which is something D&D has never handled well.) An individual person can only tap a small amount of that consciously, which is represented by the 4e Second Wind (anyone could use it; it used up your Standard action, gave you a defense bonus until the start of your next turn, and let you spend one healing surge)...which is only usable once per combat. So a person without the support of someone trained in keeping others alive (a Leader, a Paladin, someone with a medkit) or a healing potion (which was a
very inefficient means of healing) literally cannot regain more than ~25% of their HP in a single fight.
Healing surges are
the most realistic, as in actually like the living breathing people we are IRL, healing rules D&D has ever had. The only even vaguely unrealistic aspect of them is that, being Larger Than Life heroes, you can survive more total daily punishment than a real person could. But that's always been true of D&D characters from the very beginning; Gygax himself wrote about how hit points could not possibly be purely physical because a fighting-man goes from barely surviving two sword strikes to taking more injuries than a prime warhorse and shrugging them off like it's no big deal.