It makes things easier in that you don't have to worry so much about buff durations anymore. If it's becoming too much of a problem, remember that now the party won't spend that round buffing pre-battle or mid-battle and scale the difficulty of your fights to match. As always, gentlemen's agreement is in play.
The standard persistent type builds involve a lot of buffing, producing a combat machine. So, you just need to make sure any other fighter types in the group are pretty well-optimized so they don't feel outclassed. I personally have played games w/ DMM(persist) melee clerics and not felt like they completely dominated the melee field, and that's allowing things like Divine Power and a slightly-nerfed Polymorph. It's certainly weaker than a War Weaver, I think.