Is it worthy to get a Conjurer or a Monk up to speed with your party when you get those blood codes?
The Conjurer is a bit odd, the monk works ok for absorbing damage in the front, but getting equipment weapon wise for it might take a while. Though I do remember them having some pretty crazy unique weapons from the junk Ive collected near the end of the game.
I didnt use the Conjurer as much in Abyss, but am using it currently in Babel. I suppose the useful thing about it is that the contract ability to get a monster onto your side helps with taking a monster out of the fight and joins you as an extra member. Though you do not really get to control what it does. To get the more useful skills for the conjurer also help prevent the monster from running away you need to be kinda high.
Its a hard decision to make since you will be removing one of the 3 most important rear classes for it lol. Thats the downside with Abyss is that the cross blood (subjob) system was not introduced yet.
One interesting thing about the Conjurer is that its "spell" group "TRAN" its like it uses monster abilities so has a combination of physical attack, magical attack, status ailment, healing codes for use.
In regards to a high lv monk, if specced out correctly apparently it can out damage a warrior which is interesting.
I messed around with a monk in Abyss, but switched it out for an Assassin. In Babel am using one in the frontlines replacing my fighter at times, works fairly well. Good defense too in general.
Unfortunately cant be much more help than that since am not much more familiar with the classes at this point in time.