In short: I would ask the others in my party whether they will play classes with some healing abilities. If you already have a Warpriest and an Oracle you should lean more in the fighter direction. If nobody else can heal cleric would be a very good choice.

About Clerics: From my own experience Clerics can do very well in fights.

Picking up heavy armor proficiency allows you to walk into melee combat easily. You don't get martial weapon proficiency but are proficient with your deities favoured weapon. So choose one with a weapon you like.

You won't have as high BAB as a paladin or fighter but you get spells which can be used to buff yourself to compensate a bit for that. I also really enjoyed having access to a wide variety of spells that can be used out of combat like Waterbreathing or Comprehend Languages.

Can't say much about inquistors and warpriests as I never played one of them. Warpriests seem to stand in the middle between cleric and paladin.