You should really include t2 3set bonus in this and I'll provide you with the reason here.
Using the formula from this topic
http://vanillagaming.org/forum/index.php?topic=15417.0(13+ S/4)/2 * 5
to get the mp5 value from your spirit regen when not casting.
If you're fully buffed with good cons and raid buffs you'll easily be around 400 spirit when facing a hard encounter.
((13+(400/4))/2)*5 = 281,5
t2 set bonus (282*0,15)= 42,3 mp5 while casting
Also if sareks post is true then that would make it around 84 mp5, i have no real reason to doubt him since he has done the testing and has no reason to make it up.
The best t2 combo to loose the least amount of healing and stats (feel free to correct me) is chest, bracers and boots.
+35 (42-7 from spirit) healing, +13 mp5 vs 6 int, 27 spirit(=+7 healing) + the passive (around 80 mp5 fully buffed and around 60 mp5 unbuffed)
If you dont add the t2 items to the bis list then its not a list about bis items, its about max +healing and then you should indeed have
http://db.vanillagaming.org/?item=19132 as head and who knows, random green of healing items in other slots.
Sure after they fix spirit regen it will be a bit worse but still bis.