Any other tips or useful stuff is important to me, too!
So here are my thoats about all classes. Dunno if you real'y need it. But maybe you'll want to play another FC also. ><
Paladin - healer with alot of armor, can live long on his heals. One of the best FC if your team is not so good and second best flag holder.
Warrior - Best survivability if getting healed and good damage (even with no vengeance). Best flag holder in premades.
Shaman - Wolf - speed, totem - mass slow, has good healing . But I prefer them to heal FC then FC by themself.
Priest - Fear, Shield, heals. Has disorient in holy - but you shields are really bad in holy. For me the worst FC in this bracket.
Druid - Best flag bringer. Best choice if your team control EFC. Best speed, you cant CC him - so cant really damage or focus him, also has some healing capabilities. After 3-4 stacks better give flag to a warrior or paladin.
Rogue - Best flag grabber. Best choice if you need to bring flag to mid field or grab it when teams fight in flag room and get out of there fast. Also good FC support with saps.
Mage - Talking about frost - lost of freeze, lost of slow, lots of CC. Best FC support that you can think of. Also with all that control and blink can be not bad FC, getting owned only by hunters.
Warlock - Also good FC support. Fear spam + has daze in destro. Can play role of FC - has good HP pool + 20% damage reduction from pet and has some healing with drain life. Btw if enemy team has good healers - warlock will outdamage even hunters. ^_^
Hunter - Has good hp pool, one of best control and can do tons of damage. Disengage can do wonders. Not bad FC because can kill enemy faster then they kill you.
Death knight - We don't have them in this bracket.
P.S.
Anyway if you have all classes in team I'd pick warrior+healer or paladin with no healers for holding, druid as flag runner and rogue for flag grabbing and bringing to druid.