While a priest, or in particular a Disc priest might be a bit better after the changes...
Not sure that they're going to be strong enough to replace an existing toon on a working team.
If you already have a similar level/geared toon, it doesn't hurt to sub them in.

But I wouldn't go that far out of the way, to change the team up.
If it isn't broken, it doesn't need to be fixed.