How do you know what is good? (in General)

With the introduction of the new supporter item and the removal of the seeker ammo, I am seriously considering changing one of my mages from MM to CoC. My question then becomes: How would I know if this is a good change or not? One obvious test is to see who on my fight list that I could beat with MM I can't beat with CoC, but that is a biased test, since I chose my fightlist based on the fact that I *could* beat the opponent with MM. I am sure that I can come up with other metrics, but I am curious how other people validate their strategy decisions. For those that care to talk about, please clue me in.

My yardstick for measuring changes to my strat is - can I beat new people of higher MPR/PR than I did before.

I made a change this week, because an aspect of my team wasn't actually making a difference to my fights. Once I had made the change I could beat people that previously I drew against_and_I added new people to my fightlist of a much higher MPR.

Some changes take longer to work out. The change from MM to CoC is effectively changing the whole focus from ranged to melee. You may find you need to build a whole new fightlist. If they're lower down the tree than your previous then you know you've made a mistake in changing! ;)

Actually that last comment isn't entirely true. It's easier to fight up with a good ranged attack. Melee tends to take longer to find it's sweet spot.