Resource management has been a big part of the game throughout it's history, regardless of which point in that history you consider the pinnacle. If you didn't care for resource management so much, there were simpler - and often much less effective - classes to play, so learning the game was often a matter of starting with such a class, then learning others, and finally getting the 'big picture.' That's a process a lot of players never finished. It meant that the game was difficult/time-consuming to learn, intimidating to new players, and hard to master. And, that kinda limited the pool of players ready to take the plunge and DM, too.
5e is trying to be all things to all gamers, and that really should include /new/ gamers. The face of the game to new gamers will, of course, be the core rules. Where else would you start, afterall? Currently, the core of 5e is not pointed at new players or new DMs, it's firmly targeting long-time fans. Players who have deeply held expectations about classes, magic, and many other little details, and DMs long accustomed to making off the cuff ruling, in-play adjustments and generally winging it. I suppose, for a playtest, that's fine. But for a released core product, it could be a problem. Not an existing-fan-base-dividing problem like 4e was, but maybe a limiting-the-growth-of-the-fanbase one.
In a thread on the boards, a simple solution occurred to me. Take the most complex thing about D&D - all that resource management - and just excise it from core. That accomplishes all kinds of things. It focuses core on actual in-play mechanics and tactics rather than longer-term strategy. It erases the complexity of many classes. It strips the game down to a simple play experience that could be easy to grasp. From there, it could quickly (still in the PH or other entry-level product) introduce all kinds options, but it would be a starting point elegant in it's simplicity, easy to grasp, and a way of introducing new players to mechanics without mystifying them with complexity.
For instance, the basic game could be encounter-based and feature only 'at-will' abilities with minimal limitations on use and straightforward, clear explanations of how they function in game. That'd make it easier for new players - and new DMs.
That would also provide a clean core foundation upon which all the controversial options could be built up:
Hit points, for instance. Core, they'd be how much punishment you can take before you can no longer participate in the encounter. Don't even worry about whether that means you're 'dead' or 'unconscious,' it just means you're done. Next encounter, even if you're playing the same character, you start with full hps - not because you 'healed' in the meantime, but because that's just the starting condition of a character at the beginning of an encounter. From there, you could add a system like healing surges OR a system using ritual and consumable healing OR a system using only rest and time, or whatever.
Limited-use abilities, for another instance. Core, there'd be none. Your character has options, he can choose one to use each round. That's all. 0 resource management. You can add abilities that can only be used once each per encounter as an option. As a further option, you can change the recharge-rate of those abilities, making them 'daily' or 'per story' or whatever fits your campaign's pacing (and the same goes for healing resources like spells or surges or even rest & time), giving you anything up to and including 'Vancian.'