You would be reducing the skill floor for high-end as well. If you want it to be that homogenized every single job would need to perform the exact same strengths on every tank. There will always be a meta. It is an unavoidable truth in every single MMO or RPG you play. There is no avoiding it.
I play DRK all the freaking time in nearly every form of content and never get told I'm griefing the party, and never get healers that dip purely because I'm playing Dark Knight. This is the most casual of content so if anyone honestly is telling you that you're griefing the party they're just being an asshole and you shouldn't be taking them seriously.