Kensei's +25% Competence HP bonus was added onto Weapon Master, which require Greater Weapon Focus. GWF requires 8 levels of Fighter, hence you need Fighter 8 to get HP from T5 Kensei.
Can this be changed to a different enhancement (I'd pick Keen Edge), or can GWF be removed as a pre-requisite from Weapon Master, or can GWF be changed to only require Fighter 5? Otherwise it's strictly behind other T5's which support multiclassing better than Kensei does.
I've done a variety of Fighter 6 splits to get melee crit profile from Kensei, and any T5 Kensei with <8 Fighter levels is going to be in an awkward spot. Some builds can use Stalwart Defender stance sometimes, but that gives +150% threat minimum which isn't viable in a lot of cases, costs 13 AP, and requires Medium/Heavy armor or a shield.
My understanding is that one of the design principles is to encourage build diversity, but this is definitely discouraging a variety of builds I can see. I'm starting this thread because I'm writing up a 10/6/4 Monk/Fighter/Ranger Dex-max GSword build; I could go 8/8/4 and get +25% HP but then I can't get a Monk PL - and as a centered build I don't qualify for StD's improved stance.