Fireballs setting things on fire i have no real problems with - though a saving throw from burning or an optional bonus action to put out the burning person would be nice.
Undecided about additions to fighters since my knowledge of DnD is from 2nd and 3rd edition mostly - weapons already give an additional effect ( a house rule i presume ) too much change risks unbalancing the class from its party role - although i can see the appeal from a multiplayer point of view i suppose - grappling would have been interesting though difficult to implement graphically for all encounters.
My main concern is if combat encounters become designed with surfaces as part of the main balance this would have a knock on effect of reducing all other options as viable alternatives available to the player,
