Catcher is one of the most important positions IMO. They can greatly effect the game defensively, helping your pitcher (s) produce more outs and also throwing in some offense as well. While nothing beats having an ACE starting pitcher, having a good catcher is a close second. Then of course, strong up the middle applies as well.
When looking at catchers, I always try to get a high PC coupled with adequate offense. PC comes first. If I roll into a catcher that just mashes and is near 50 PC, I will play him, but will then pair him with a 90+ PC guy to finish games off.
As an edit, if I do have a masher low PC catcher type, I will also look to move him for pieces I do need. Nothing excites a good trade opportunity more in this game that lighting up the other guy's MDS (Mesolimbic Dopamine System - not related to the game lol) with offensive ratings. Offense is great, but personally I always look to fulfill my defensive needs at every position first.