Oh for sure man.
But an invisible creature moving around in a normal combat is not one of them. For example you said:
Those are all situations covered by the RAW on hiding.
1) Invisible paladin in heavy armor? Likely dumped Dex, does not have Stealth (and has disadvantage from the armor). When he tries to Hide (via the Hide action), he likely fails.
2) Monks and especially Rogues already have abilities that let them [Dash AND Hide] all in the same round (or Dash AND Dash again)
3) There is no 'half movement Stealth' rule in 5E. The movement penalty is already accounted for via needing to use the Hide action (instead of the Dash action).
- A Wizard trying to be stealthy while invisible moves 30' (Hide action, and then moves)
- A Wizard NOT trying to be stealthy while invisible moves 60'. (Dash action and then moves)
- A Rogue 2+ trying to be Stealthy while invisible moves 60' (Hide action, Cunning action Dash action, then moves)
- The same Rogue not trying to be stealthy moves 90'
- A Monk 2+ trying to be Stealthy while invisible moves 80' (Hide action, Step of the Wind Dash action, then moves).
- The same Monk not trying to be Stealthy moves 120'
See how it works? The action economy of requiring the Hide action, represents an opportunity cost that slows down someone trying to be Stealthy. Someone who isnt trying to be Stealthy can always move faster than someone who is trying.
And thats the RAW. No need for 'rulings' on that or Acrobatics checks etc.