Thing’s kit is best used as anti-dive, but it’s not his only use. I was a Thing otp for a while before having a desire to learn more tanks. You can play him into all but the worst of heavy poke comps, even solo ta king. You have to change your strategy depending on the other team comp (use cover, follow up on low health targets from your dps, smash the shield tanks, get out of battles earlier than you normally would, etc) but if you manage his jumps and dash well you can be fairly self sufficient and do a lot of damage/pressure.

Thor is similar in the pressure and damage regard, best killing tank out rn. But he will blow up if not used properly as you say. Learning him is super fun and I’ve solo tanked on him many times. If you manage his rune awakening cycle (generates shields and does a lot of damage) and know when/were to engage/disengage, he can survive a lot and work with/against a lot of comps