One of the primary reasons behind the 3.0.8 armour nerf was that we were getting very close to hitting the cap. Now with 3.1 we're being told we'll get a new shield-mechanic working off offensive stats, but they want to nerf our armour further. Natural reaction is probably to think that maybe Blizz sees us closing in on the cap again in further tiers, so let's check if that's the case, or if a further armour nerf combined with a potentially weakened block-mechanic(can only mitigate one hit after a crit) is wholly unjustified.
First some quick examples of gear at the current iLvls:
iLvl 200 564
iLvl 213 578 (+2.48%)
iLvl 226 591 (+2.19%)
iLvl 200 494
iLvl 213 506 (+2.44%)
iLvl 226 517 (+2.17%)
Now the numbers for all 8 slots of leather gear + the cloak slot(assuming no bonus armour as it's not multiplied anymore):
At iLvl 200 armour from gear is 3394
At iLvl 213 armour from gear is 3480 (+2.53)
Projections for the next tiers:
T8.25: iLvl 226, total armour from gear 3567 (+2.5%)
T9.25: iLvl 239, total armour from gear 3656 (+2.5%)
T10.25: iLvl 252, total armour from gear 3747 (+2.5%)
After applying current armour modifiers(8.58) we get:
T7.10: iLvl 200, total armour from gear 29120
T7.25: iLvl 213, total armour from gear 29858
T8.25: iLvl 226, total armour from gear 30604
T9.25: iLvl 239, total armour from gear 31368
T10.25: iLvl 252, total armour from gear 32149
Conclusion? With the current modifier and assuming no bonus armour items we'd still be short of our pre-3.0.8 potential numbers even at a theorethical T10.25 gearlevel. Barring some pretty crazy bonus armour items we can all but kiss hitting the cap(49.905 vs. lvl83 mobs) goodbye.
So then what does that mean? It means we're getting a sub-par block for tanking trash whilst losing out on the best scaling stat against hard hitting physical bosses. 3.1 doesn't make us any more healable, and as such doesn't enable us to scale with stamina as we could. There's not relief for our single avoidance mechanic which is allready hitting the DR. In short? At current time, unless the effectiveness of this new shield is truely insane we're looking at a nerf.