Certainly looks useful, but I'm not sure why a druid would want to spend this kind of slot and concentation on plain protection...?

If its range was even touch, it could be useful. But it’s kind of trash instead.

Yeah, I'm not sure what place this spell has being 6th level. If the reaction didn't cause the spell to end, that'd be neat. Comparing it to something like circle of power, which provides advantage on saving throws against all spells and magical effects to yourself and allies in a 30-foot radius, and in addition causes them to take no damage on a successful save, primordial ward just feels so limited. Yes, there's a lot of attacks/effects that are not cast from a spell or are magical in nature, such as a dragon's breath, but I feel the amount of use you'd get from this in comparison to a lower level spell is pretty small.

It's best use I suppose would be the ability to prepare it, since it's on the druid's spell list, for a time when you know for sure you'll be facing a lot of those damage types, such as traversing the elemental planes or something similar. Even then, using your most likely singular 6th-level spell slot on it still seems like a big commitment. At least it doesn't consume an expensive material component like stoneskin.

I should add, primordial ward also only lasts a minute, so even being able to prepare it, it'll only last the duration of at best one encounter.