Na, my smiter DESTROYS casters unless they a 200% FCR lightsorc that uses CB, then im like a fish out water in the desert with a empty water bottle.
What I use to kill casters is COH with a Exile shield, Grief Phaseblade and...some helm with lots of res. I cant remebr then name at the moment.
If your going aginst casters use COH but if your going aginst another smiter or any melee char uses use fort. The extra damage will make u easly kill them in 1-3 hits. There is no way a melee char can beat smite. But i will admit that the 200%fcr light cb sorc will give you lots of troble. They shot really really really fast.
No one should make a smiter. You should make a zealer. Use zeal against minions and smite (1 point) against bosses. COH is best armor in game because resists, +2 skills and reasonable defense (especially with Holy Shield).
I pvp ALOT, and since you did not ask about a zealer, I'll tell you what I've seen from the best smiters on East. Generally, if you can afford the resist through other means, coh is rather useless compared to enigma for a smiter. Enigma adds more health, str, and has other great mods, and, of course, teleport. The best smiter I've fought have ALWAYS used enigma. It simply adds the most and another choice of dueling stragety, since you can tele and charge.
Teleport to me can be traded out for charge simply because when tyou charge, it gives a good chance to lay down the smack when you get to the enemy. against most casters, one charge with decent gear will kill them. against casters I use CoH for the resists and the +2 all skills (helps since i have 1 point into charge). for melee characters, I use fort for the extra armor (chilling armor) massive damage increase, and life. thats just my opinion though.
use nigma made in a breast plate that way you should end up haveing to put no points in str at all ( anni and torch ) and the rest will go to more vita problem solved and theres not really much of a need for def if you play vs casters and other smiters anyways
other wise make in a dusk but definitly nigma the + to str will save alot of points to equip your other gear and add lots to life