I've been playing in a Kingmaker campaign for over a year now and the group has been pretty steady in its advancement. We're relatively balanced:
-Switch Hitter Ranger and Elk Companion
-THW Fighter w/ Adamantine Greatsword
-Universalist Wizard
-myself, an idealist Cleric (dedicated to the kingdom's ideals rather than a specific deity and staunchly agnostic) with the Nobility and Protection domains.
The party is just back from a hiatus and we were allowed to rebuild ourselves a little since we made a decision to go Core Rulebook-only for character options. I had been an Oracle of Life so my current Cleric build made the most sense. Trouble is, I'm bored out of my mind, especially with the Ranger and Fighter laying waste to everything they meet and a Wizard whose spell list seems to outstrip mine in most combat scenarios.
The saving grace of the character is that I've yet to get a failed save on my Calm Emotions casts which usually buy the party a few rounds during those "Oh Sh*t we're dead" moments, and my Channel Energy feature is the only healing source.
But that's still boring. I'm thinking I'd like to rebuild to something a little more versatile than just a healbot with the occasional party buff, but I'm short on ideas.
tl;dr: Cleric healbot role is running thin in Kingmaker campaign, alternative class suggestions needed.
Do a non healbot cleric? Oracle of battle?
Take a look at the List of Guides, and see if the Cleric Guides can give you some inspiration.
I would see what domains I like best, and then work backwards to pick a race and diety that fit.
There's an awesome and unusual "Reach Cleric" explained there. Does reach combat and touch spells.
I had a friend play a Cleric of Besmara, with a 2-level dip in Rogue. More of a Tricky-Sneaky kind of cleric. But had domain abilities like mirror image, seeing thru walls, and short dimension hops. It looked like fun.
The party clearly needs a divine caster. Either just pick a different cleric build, they do not have to be healbots. Oracles are even more varied. How about either an inquisitor or a druid?
We had a similar issue with our cleric getting bored. In the end we bought a custom staff loaded with Heal and a crate of CLW wands and we had the summoner act as party healer but really any UMD class can pull it off. If you are dominating as much as you say than you can probably get by with only a few big in combat Heals and then clean up after with wands and scrolls
We reduced back to Core as an experiment. We'd played another campaign during the hiatus (break was due to DM fatigue) and tried focusing on using materials that were available only at the time the AP was published. It went rather well and we decided to give it a go when we came back to Kingmaker. Lately there's been some push from the players to expand so the DM is considering going to Core race / class but non-core for other options beyond those.
My other issue could be that I have a stat array of Str 9, Dex 13, Con 13, Int 11, Wis 20, Cha 14 after racial / lvl and item bonuses. (Human lvl 7 with +2 wis item). I'm not great at much beyond casting, though part of that was in response to needing better spells.
I also second Haldrick on Druid if you have any desire to go that way.
Kingmaker is the best AP going for Druids. Lots of time outside for weather control, and a huge variety of critters to summon.
You'd get to Wildshape to fly or swim or travel thru the earth. There are no better scouts than wildshaped druids (who's going to give a second thought to that sparrow sitting on a branch nearby?).
If you focused on it, your Wildshape could be an awesome fighter.
There's a lot of variety of skills with Druids. You wouldn't be the best fighter or the best caster-- but you'd have a trick up your sleeve for every occasion.
And... at the end of the fight, oh yeah, you could throw a few cure lights from a wand. But you would have many great options besides healbotting.
We don't have the funds for much in the way of magical items so we're pretty much at the mercy of the mod - that being said when we started up again we were allowed to build new 7th level characters so we're each outfitted with armour, weapons and the like. We can probably start channeling funds into spell-boosting items.
I don't summon much - that's more the Wizard's deal since he did pick up a Rod of Extend - but I played with it a bit more in our last session. I'm thinking I might look at doing it more, but the Sacred Summons feat is pretty much out. I don't worship a deity and if I did, the way my RP is going it'd probably be Pharasma, whose neutrality doesn't lend itself well to getting a Standard Action summoned creature.
Alignment wise I'm NG and staunchly against Undead. When we started I was an Oracle of Life dedicated to erasing Undead from existence and the Wizard was a Necromancer. We had several philosophical disagreements.
I'm leaning towards a druid or doing more summons as a cleric. I find that my biggest issue is action economy when there isn't healing to be done. With poor physical stats and a limited selection of battle-ready spells that don't buff my personal attacks, I don't have much to do. A pet or cohort would give me more to do at the table as a player.