I have a horse, and the head thing does not bother me at all. Sometimes I have to look up in my buff window to see if I'm on my horse (shiny things distract me easy).
I use hot buttons for just about everything, so targeting is not an issue - though if I do try to target something by clicking on it I might have trouble 30% of the time. The biggest problem is looting stuff - but I think it applies to any mount. Hitting F9 and changing to the overhead view fixes this, also coming up to the side of the corpse will make it easier to loot. I also use a pet trick (mage) - hot button that says /assist /loot - I target my pet (or if another person has it targeted I can target them - but your pet will always have the corpse of the last thing it killed in its target), hit the hot button - this also works well for mobs that die in walls, and those bony whirlwinds in dungeons that I can never loot. Rare occasion I just dismount and loot.
I prefer to play with people that have horses, because they are not as wide - but alas everyone has a dino because everyone is afraid of the head... the head is really not an issue - I don't even see it unless I'm moving.