I really don't get how so many people had so much trouble in this place as a melee. No, really, I do not understand how it was difficult for you. Warriors had Charge, Paladins have Judgement to get the mobs to come to them, Rogues have Shadowstep to get in range or Throw to get the mobs to come to them, Druids had Faerie Fire or Kitty/Bear Charge, Death Knights have Death Grip and ranged spells to get the mobs to come to them, and Monks have the ability to make mobs rush them as a tank or ranged attacks to get the mob to come to them. If I recall, Shamans also have the ability to make things come to them, so not a big deal.
Looting was hard? How was looting hard? If you were fighting something as melee, it's corpse is RIGHT THERE BESIDE YOU, FLOATING WHERE YOU KILLED IT. Or, in the cases where they didn't float, they just dropped straight down where you could pick it up in two seconds. The swimming didn't feel slow because you had Sea Legs which boosted things significantly, and the Sea Horse didn't take that long at all to get so you were zipping around at faster than maximum flight speeds.
It looked awesome, it had a lot of great quests, and yes some of the places for mobs, drops, or NPCs were a bit awkward to find, but I never really minded that much since I tended to remember after the first or second time. And if it happened again? It was probably because I was zoning out and not paying attention, in which case I can't really blame anyone but myself.
Yes, it was also impossible to use AoE spells in the middle of the water, but if you don't like that, then you have the option in a lot of areas to stick to the floor of something and attack mobs that way. How was casting a pain? I don't get it at all. I loved Vash'jr and found it a lot more interesting than Hyjal, and leveled far more alts underwater than above it.