Why not just make everyone a DPS?

[Risvertasashi]

This game has no variety as there is only 1 mathematically optimal build which happens to be the same on all classes. Weapon Damage > Main Stat > Crit > Determination > Speed. So you end up with everyone, whether they're DPS, tanks or healers, going for the exact same stat builds. Stats are also linear with no caps or diminishing returns

There is so much wrong with this. Crit has diminishing returns and isn't the most optimal off stat for all jobs.

I don't disagree with the general spirit of your post but do be careful with the facts you lay down.

force crits benefit far more

For guaranteed crits, jobs actually benefit less from the crit stat and more from det (since det raises the damage from the guaranteed crit). Now there's some debate about whether det is actually worth it but it is an argument that some MNKs (for example) make.

There is no actual diminishing return as in each point of crit gives exactly the same % of crit chance, this doesn't change no matter how high you go in crit. The stat value doesn't change and each point is as good as the previous one. Crit is as linear as any other stat in this game.

I was about to say this isn't consistent with data I've seen but it seems the theorycrafting subreddit has disappeared O.o Well... guess I'll just wait until the Heavensward numbers are in a verify if crit diminishes or not.