He looks fun, and I've also really liked the Commissar Cain books. I to, as soon as I finished felt a strong urge to write rules for him, as well as Eisenhorn, Churbael... Its not a rare urge
I think Commissar Cain deserves
Ws 6, because that's what genestealers are and he tangles with them every other day it seems and comes out on top! He should also be
Bs 5, because he rarely misses and I5. He is a fighty commissar, despite his own misgivings, but lacks a power weapon, you have to make up for it with better stats. I think the double model base is a cool idea, but I think they should both stay alive until the end (No killing off Jurgan before his duty is done) and they should both use the 4+ save.
I agree with the no warlord thing, nice touch. But you need to lose the strong odour ability, because they need to join a unit to survive. You can simply say as long as he is with another unit, he counts as
Ld 10, but when not in a unit he is
Ld 7 (No one to see him run away!). Then say he won't excercute anyone but peril'in psykers and your done. Otherwise they a 4 wounds with a 4+ save,
LOS or not, they aren't survivable. I think he deserves eternal warrior, simple because the
IG have none yet, and every codex needs at least 1 but I think you should add in a 5+ invul to it as well simply for luck. I think Jurgans webbing is a bit unnecessary, when you could simply add the webbing to his wargear and say it contains melta, frag and Krak grenades. I like the Null thing. Maybe you could replace the webbing with some extra combat oomph, which I think he needs. Think of all the things Commissar has fought in combat, a chaos lord, several hive tyrants and a genestealer patriarch, you don't do that on
Ws 5 with no bonuses.
I was thinking maybe a 'Parry' kinda rule where Cain reduces his attacks by 1 to negate an enemy attack, potentially to nothing that would also increase his invul to a 4+ in combat. Then simply add rending to his weapons and give Jurgan an 'I've got a shot, sir' special rule where at I 10 Cain may pass an I test to roll out the way so Jurgan can deliver a
Ws 5 strength 8
AP 2 'Hit'. Cain may make no further attacks if he does that.
What do you think? I think i'm changing it a bit to much maybe, but im just giving ideas if you like them. Long story short, give him more combat Oomph and make him join units and you done.