Considering you have no more Vengeance, that would always cap your Shield Barrier to the X*Stamina minimum part, which, through Resolve would cause the majority of it to scale exponentially.
Luckily, the Warlords version (http://wod.wowhead.com/spell=112048) now simply does 7.5 * AP at max Rage, making it easier to understand how it works.
Assuming the Riposte change will be X% crit = X% Parry, we will be looking at 110 crit rating per parry and ~233 Str per parry.
One would assume both sources get affected by DR (otherwise crit will become godly at endgame, see Sunwell Radiance)
I like that, based on your AP, you bring a certain amount of healing to the board, regardless of wether you're tanking or not. Several DPS classes already do the same, such as Bloodthirst, Warlock Soul Leech, Priest Devouring Plague,... It allows for a sort of group-play feel, helping out healers. Resolve just makes sure you have that extra button to press that scales with incoming boss damage, sort of a smart-use demo shout or something.
We saw that resolve is something that works better the lower your equip is.
I had some concerns about it, and can't see any real reason to introduce it in the game. It is presented as a replacement for vengeance, but it doesn't address anyone of the "problem" vengeance is supposed to solve. As I can't find a reasonable because for it I tried to change my point of view. What problem is resolve addressing? Can be the counterscaling things a pros? I think it can be so.
Resolve is to address the "beginning" of new tier problem, the first week of progress, when you are under equipped. Actually we start with really hard times, with a whole raid in sub-par equip, the new encounter to learn etc. It is funny, probably the funnier part of the game, but it stress us a lot and there isn't much fun (at least for me) when you have to give up because you see you simply can't got the kill, you need better gear. On the other hand when you are full equipped for the content your raiding is quite boring and a wipe something that usually happen only because you are stressing on the time component, solo tanking, using less healers, not doing adds, forgiving cc etc.
The counter-intuitive Resolve mechanics can't completely change it, but it can smooth the step a bit. At the beginning you will take less damage thanks to resolve, while you other mitigation are sub-par, as you hit pool is lower the risk higher, but you require less healing from sub par equipped healer. When you progress your other stats will improve, and so will do the healers throughput, making easy to heal the increased damage.
It is just an intuition, but it makes sense to me.