I don't see anything wrong with the current UnderDaSea map (for 1.8 or 1.9) since it's more combat focused now. Sure you can't easily hit players off but that should be a good thing as no one wants to be hit off and die without a fair fight. The current map layout forces players to actually engage in PvP which in my opinion is a positive compared to the old map layout. If you are having trouble killing someone because they out-gear you, you just need to gear up before they do or consider alternate strategies to kill them. There are other ways to kill someone besides hitting them off the edge even if they out-gear you. This map may need another revamp or may get one in the future but currently it's pretty good as it stands.