There's both sides of it really.
If you want to level up fishing you have the choice of fishing manually, or automatically - granted iirc automatically is a lot slower.
Gathering professions etc you have to go do yourself.
You can close the game to System Tray whilst doing an "Auto Loop" to level up your weight and running skills etc? (Who came up with this?!?! )
There is a lot of fighting grinding too, big wars happen if you can find a guild who do it - node wars etc.
It's definitely fun, but grinding is a big factor. - Levelling up your gear is very RNG based too, want to upgrade something? Nope! Sometimes it can even destroy the equipment!
Questing isn't necessary but there are advantages to doing them, which was beneficial to me, as I despise questing (did them after I reached level 50 anyway... ugh)