It's only pointless to level a job if you don't like playing the job.

You like the job, you like the aesthetics, then just go for it. PLD indeed has a lot of issues right now but this is an MMO game, constantly evolving, meaning that this could change in any of the future patches. And even with its issues, it can still clear the content. If you like the job, play it, that's as simple as that.