likely solves a lot of problems but you still have the problem
@Don Durito mentioned and stuff like monks being able to make flurry the default action & possibly flurry+stunning strike+possible archetype goodies for 3 attacks with extra benefits most if not every round on top of all the other cool monk features once the party starts resting after every fight while fighters don't get a third attack till 11... Normally the fact that the party is unlikely to rest after every fight limits that considerably but not so with your fix.
It doesn't end there for fighter problems though,second wind & action surge back on a short rest, everything seems ok until you notice battlemasrer & psi warrior get back superiority/psionic energy dice on a short rest & rune knights get back their rune while many other fighter archetpes get bupkis.
It doesn't end there either. Your spell slot rejiggering might work fine for a land/shepherd/etc druid, but for a moon druid it means:
- always have two wildshape forms but fewer spellslots to heal with so any tough fight will knock them out rather than taxing their slots.
- at 11+ they transform into a earth/fire/water/air elemental for 5+ hours & after the first fight or two have a second fresh one waiting to go plus some spell slots to heal it.
The more you look, the more other class & archetype specific edge cases that will either be broken or make someone's life miserable until you introduce yet another one off fix you can hope won't prove problematic just to support this change. This sisyphean task
should be a positively trivial change, but WotC set you up to fail on this matter by pegging short rest classes to higher bar than long rest on the assumption they would often run low & fall back & that's the kind of stuff people were alluding to upthread.