Buffing VIT Nerfing STR - Some simple math...

[Reynhart]

I think this depends on one big thing, and I think it's why some tanks don't want to give up their damage for more VIT.

The thing is...you have no choice now. Maybe stacking VIT will make you deal less damage than nowadays, but stacking STR will be even worse.
And, since we're getting an increase in ilvl, you won't really feel the difference, unless intentionally keeping your ilvl "low" for Midas Savage, since your overall damage output will increase.