Here's what Riot's said about the Resolve mastery tree.
The Resolve tree provides some solid options to make champions tankier, but ironically falls a bit flat in supporting the tank playstyle. We’re adding choices that reward tanks for actively doing their job rather than continuing to make them passively stronger.
So why exactly is it alright for damage classes to become passively stronger via masteries, but not tanks? Considering how poorly balanced tank vs ADC/APC is at the moment, you'd think tanks could use a little boost to their passive strength, as opposed to the extra damage you're giving to champions...yet again.
The more I see mastery info, the less I'm convinced that Rioters actually know what they're doing.
were taking SOTA to get early tank stats to duel better, sustain better, and be tankier. Riot noticed this and realized it was an issue, they say this here