At the risk of being somewhat premature, Dracovich, I think I'd have to say 'Yes, +8 seems to be about the top, right now'
I played with some stuff last night with my mage and my warrior (mage is 110 magery, 100 invocation). The highest protect spell AR boost my mage could get - casting on himself or a volunteer warrior - was 8. I'm thinking that 110 magery with 110 invocation *might* give a +9, but I haven't been able to test it (anyone else try this yet?).
Later on - after his buffs wore off - I had the mage use a protect wand to cast, and it was still +8. I then logged on my warrior and had him wand-cast protect on himself.... +8.
On the other hand, the duration was in the high 35+ minute range (I think 38, but not sure). That is certainly nice for the warrior , as he used to average +11 or +12 with those wands and has a much higher AR than the mage does - even unbuffed, and a drop of 4-5 pts is not a big deal for him, whereas the extra 10 or so minutes are *much* more useful.
On the other hand, *pauses for a second to count hands .... yep, all 3 are there:) * I also noticed that there did not seem to be any corresponding lowering of the negative effects of MOB Unbuff spells (curse, weaken, etc.). I was still getting hit with -11's and -12's when I got de-buffed.
While my verdict is still out on how much and in what way this reduction of the efficacy of the buff spells is going to affect my playstyle, I do think that the negative capability of the MOBs should be reduced. Maybe not as much, but at least by a good percentage of the amount the buff spells maximums were lowered. (*gak - didn't THAT paragraph sound pretentious?).
One last observation I'd like to make about the change. It's not to be taken as negative or positive, just an observation. There is now a *very* significant disparity in the duration of the effect between the wands/spells and potions. Spells/wands are showing the lower effects, but longer duration. Potions are still the same as they were. For my warrior, that means potions last 26 minutes, but wands last 38 minutes. Folks (like me) who use both wands or spells and potions for buffing should keep this length difference in mind.