i have returned to WoW (skipped MoP&half of Cata) left at start of cata
afew weeks since and dinged 100 on my main charater
but i have been missed a addon and a program that helped me alot in the past
-Rawr(the program):
https://rawr.codeplex.com/
-RatingBuster:
compare gear and also convert ratings to % aswell as convert Int/agi/str to Spell/attack power so you can see how much power or % you get from stats&Spec or talent aswell
it even worked with something like Shadow priests Spirit to Hit rating convertion talents back then
i have been tried something like Pawn but it is not the same at all
and Rawr was so good to help me plan what items i should go after to get a really good gear setup
and see what is upgrades or down grades and you could save the Gear setup if you close the program and open it again
but will be happy to see if there is a addon for ingame that is 100% like that or close to it