pardon me what?
For one thing, no, theres no surface rules in DnD, thats because DnD is a very simplistic system, however, i can tell you that almost every DM who once had enemies submerged in water was forced to houserule that exact effect at least once.

and yes, surfaces are overtuned right now, doens tmean they should be gone.
If you only want things that ar in the rules, youll have a very shallow game. 5Es rules are deliberatley simplistic and are more of a foundaiton than anything else.