In the DM manual there's reference to something like 'By a quick rule of thumb if there's a situation where a character would have a bonus use a +2 to the roll, if they're impaired in some way use a -2"
I'd say DM discretion... or impliment a house rule of +1 or +2. I'd only use this is extreme circumstances, possibly only ranged with higher ground of 5ft or more (1 square in height.)
It's not in the PHB, but I still use the old rule.
No horrible consequences... just I don't see any particular advantage in the mechanics for it happening all the time.Could I ask why only in extreme circumstances? It seems to me like a small bonus for jumping on a table or whatever would encourage movement and might open up a few more interesting tactical choices in combat. Do you foresee any horrible consequences?
Whatever you do don't use the Star Wars d20 Revenge of the Sith rule... "if you hold the higher ground you can cut off both your opponents legs as an immediate interrupt..."
The way I do higher ground is a bit more natural. Higher ground has a chance of reducing total cover to simply cover, while providing cover to the higher person.
You know, the -actual- advantage to higher ground.