Never confuse an MMORPG with an RPG. RPGs are single player games and you do whatever you want, however you want; MMORPGs are multiplayer games and if you play with other people you do what is expected of you, you dont play bard with pie gear for example.

14 has three roles: tank, healer and damage dealer. If there's one best way to gear spec for damage/healing then yes that is the way and any other way is just wrong. If you're over geared then playing less than perfect isn't an issue but early on it can be an issue.

I spent yesterday doing Void Ark, we wiped three times because fist of all people were not playing properly so damage was low and secondly, the most important they were not moving out of stuff they should. The other healer let the faerie do most of the healing so I had to do most of it.

Do what you want yourself but not when you play with others.