I would argue for... arcanist branching off to summoner job as the best solo dps in terms of... surviving. Having a pet tank the enemy while you dps and are in no real danger makes solo content a cakewalk.

Based on your information given...

Pros:
-Caster = ranged
-Tank pet for solo play
-Melee and caster pets for dps in a group
-Easy to play, damage over time (dot) enemy up and win

Cons:
-Main damage is from damage over time spells chipping away at enemy health, and 30 percent of your damage is from pet, so you may not "feel" powerful


But, honestly any class/job can do the current solo content. You can also get a chocobo companion at level 20-ish and spec the chocobo into a tank/healer/dps role as you like, if you want some extra help.