This doesn't make much sense to me. If they felt GEO was too powerful in term of endgame, they would have adjusted it by the time Reisejima and Escha came out. They wouldn't have designed 50+ end game mobs so you can only do it with GEO.

Even for low content if you don't take GEO you're only slowing yourself down.
You can replace GEO here with BRD and COR and it would be the same in this case. Supports jobs always make things faster. It's the whole point of them!

I feel like a lot of frustration here come from the fact people cannot find support jobs (especially on less populated servers).