Pemerton, re-reading your reply, are you suggesting I should pay attention to the "economy" of combat encounters & short/long rests in 5e?
Say: we don't do much dungeon crawl, nor use AdvPaths, is that going to be a problem, possibly a game breaking one?
This gets into fairly contentious territory - but my answer is a firm "yes", and it's probably the main reason I'm not very enthusiastic about 5e as a system.
I'll elaborate - I've got two reasons, a primary one and a secondary one.
The primary reason: in a system (like 5e or 13th Age) with strongly asymmetric suites of player resources, the balance of intra-party mechanical effectiveness can easily be broken - normally by those players with long-rest-recovery deploying them in a nova fashion, and then taking steps to recover them - which means those players with short-rest recovery or at-will resources don't get the benefit of their more rapid recovery times.
13th Age solves this problem by sheer stipulation - after 4 combats the players get the benefit of a long rest - but that feature of mechanical pacing puts pressure on the GM to shape the fiction and the in-fiction pacing in such a way that the recovery makes sense.
The standard recommended approach in 5e is for the GM to exercise very strong control over the pacing and the availability of rests, which then generates uncertainy on the parts of the players about the prospects of resource recovery, and thus reduces the tendency of players with long-rest-recovery resources to spend them profligately.
But that leads into my secondary reason: the result of resource-conservation is that, at least some of the time and perhaps quite a bit of the time, you don't get to
play your PC (in the full mechanical sense of that notion). If my conception of my character is as a fireballing blaster then I want to
cast fireballs, not conserve them!
(I regard classic D&D as an exception to this - in classic dungeon crawling RPGing the PC isn't really a
character to be
played, but a suite of resources and capabilities to be managed. Converving appropriately is part of that. But it's far from my favourite approach to RPGing - I prefer more contemporary styles where player mechanical resources are the devices whereby the
character is
played by engaging with the fiction and declaring actions.)
The last system I played/GMed in a serious way that had asymmetric resource suites was Rolemaster. In my first long RM campaign we solved the problem by having everyone play wizards (so while there was asymmetry in the rules, there was not very much at our table). In our second long campaign we tweaked some rules and also adopted some conventions which meant that, as a general proposition, a caster had to nova to be on a par with a non-caster - but had a degree of versatility and supernatural capability (eg non-casters can't fly or just turn invisible in the middle of a plain) which made up for this lack of sheer effectiveness.
But for the past 10 years I've only played/GMed games with symmetric resource suites, with the exception of a couple of sessions of AD&D (which fall into the paranthetical exception noted above).
Edit: Re APs - I would never recommend APs (!) and by all accounts the published ones for 5e don't do a particularly good job of managing these pacing issues.
I think not doing dungeon crawls makes the presupposed pacing of 6-8 encounters per adventuring day harder to pull off - a fairly standard solution (that many 4e tables also used) is to upscale short/long rests to 1x/day and 1x/week. (An alternative to 1x/week is
you must be at a haven/safe place, but if you mostly play city or courtly adventures that mightn't help.)
The real issue is managing pacing so that nova-ing of long-rest-recovery resources doesn't become a dominant strategy.
