I don't agree. The use of hunger introduces more difficulty to the server. It can be tweaked for some classes to decrease or increase more depending on who you are. It also applies a greater use for food on this map, and as someone said, will heavily increase the market for those items.
To be honest, in certain conditions, playing on the server is easy. If you do things right, you have no danger from MOBS or other players. This is why a food bar is needed. It will help keep people in a somewhat danger.
Also, if there was no hunger bar then players could just keep sprinting and doing other tasks without getting tired. They could do them endlessly.
Using at as a mana bar just gets rid of these idea. I mean, there is no point making it a mana bar because it just wastes to much potential in the game. Why not use the EXP bar as a mana bar or something? Ya see the exp bar is something that has NO use at the moment. I know a lot of players that do not even use the mana bar.