Yeah, I don't know what the reasoning was with not including the exploration stuff, they talked about it as a 'pillar' during the much-vaunted design process, but then just basically ignored it. AFAICT 5e is aimed squarely at reproducing 2e's game play. 2e did the same thing, it took 1e and ripped out all the exploration stuff, made it much harder to do things like create magic items, and then subverted the old GP for XP mode of advancement.Honestly, the disparity between short and long rest classes is one of those design decisions in 5e that has me scratching my head. There are plenty of things in the game that I might not like, but do understand; but that one seems to serve no purpose other than to create problems.
I really wonder what kind of game 5e was 'supposed' to be. I know opinion here leans towards trad, and I can see that, but you'd think that sort of game would be poorly served by the balance problems that occur with the attrition-based, short rest/long rest system they went with. On the other hand, the playtests had some honest-to-God 'old school' exploration procedures, and even a version of Keep on the Borderlands, but that all got ripped out in favour of DM fiat and linear adventures.
Maybe if I'd actually played any 3rd Edition (or any official adventures for second), I'd see more of a family resemblance.
I guess you could say that the play of 2e is well-known to a lot of older players, and is the last TSR version of D&D, the last one that is really seriously mechanically a child of Gary's own handiwork. So, evoking it may have been a sort of mandate, a way of insuring fan loyalty. I mean, 5e REALLY is sort of 2e reborn in a more robust set of rules. That also explains the whole resource thing, its not intended to be a clean sheet design of a resource system, it is exactly delivering all the quirks and foibles of good old vancian wizards and TSR fighters, though with a reasonably decent job of filing off some of the rough edges. Certainly a 5e fighter is a bit less vanilla than core 2e ones, though once you add available kits and such they seem fairly comparable (sort of depends on which 2e books you would consider reasonably usable, like NOT 'weapons and tactics', lol).