So I am running around with a wand of warding +3 and a wand of warding +2 on a gladiator file. It is a useful wand, but is it really the top-tier wand that some people on the internet seem to say it is? The Greater Sentries can be killed, and they even lose health by firing. I could see them being OP if they did not cost health to attack. But the way they are now, if you want them to survive, at least at deeper floors, you have to feed them charges to try and maintain their health. You could have spent those turns directly attacking the enemy instead.
Is there something that I am missing on how best to use the wand of warding? What are the best strategies to take advantage of it?
Nah. Wand of blastwave best wand no contest, wand of corrosion second best wand when upgradeless (behind wand of blastwave) and best wands when you have lots of upgrades to pour into are both lightning and freezing, preferably ligntning, as freezer deals less damage if an enemy is chilled and has less base damage.
Those are the two wands that have the best scaling with upgrades. Another fine option if upgrading is disintegration. Not as optimal as those last two, but still has decent scalling.