Must not be, I can think of all sorts of ways I'd use this, and nothing about this tree (least of all that silly Wis capstone) punishes multiclassing let alone splashes.
You get that the most you're liable to spend in a single tree is about 40-ish points if it's ful of good stuff right? I say that because I keep running into people complaining about single trees like they are duty bound (or flavor bound) to only use one tree. You've got 40 odd other points to put into a Melee tree... so that being said imagine not min maxed or anything a 12 cleric 8 fighter Kensei that uses Kensei tree and this tree... Better DPS than a Pali almost certainly and no S&B focus. Better heals by far... limited group healing but you were talking about a battle cleric right?
Kensei +4 to hit and +4 damage +1 crit range (maybe to Schimy?)
WP: +4 Enhancement level, put a devotion ruby in and your +8 CitW weapon becomes a +36 spell power casting implement
without even cooking anything else that's +8 to hit and +8 to damage 36% boost to all spells. (Note not offering this up as a build to be critisized just responding to the idea that WP is a bad idea for a melee soul or Battlecleric.
My Elf AA pure FvS max Wis based (and zen archery) casting/Ranged light nuking FvS is salivating at that enhacement bonus impliment bonus boost. and even the Capstone seems worthy of taking. Probably will stick with the free searing light SLA or splash 3-4 cleric for some other light SLA's but you never know.