Good commentary, ntropy.
Kira and I were definitely playing with a budget compared to our opponents - I was consistently an item or more down on Dark_Satana, because we were focused on saving for upgrades. If they had been able to out-DPS us it might have been an issue, but that wasn't going to happen with these DGs.
I wasn't looking for this, but it just occurred to me that I don't think NinjaAlk and Dark_Satana were stacking their priests. I'll check the replay, but if I were playing Oak/LE against a mixed team the first thing I would want to do would be ensuring that each of us had a L1 and L2 monk and leapfrog up from there. If they weren't doing this then it was a serious oversight.
I'm leery of using shield early against Bite since he still gets his heal - blocking 750 damage might not be worth the cooldown, but I'll try kiting against LE more. I confess regardless of build my Oak finds it difficult to take on good LEs in anything less than a 2v1 until 10+ just because LE can be so tricksy
Good to see you think Spirits can be viable. Some of the comments here and in other Oak threads lately are along the lines of "Spirit Oak will NEVER defeat Assassin Oak AAHH HA HA HA HA HAAAA!!!"
Re: 3v3 - Penitence spam is nice, but I tend to spam Surge and save Penit for the interrupts/chases even when I max it. I think you need the interrupt, and the debuff is amazing, but I've played high level 3v3 with a single point in Penitence and it hurts less than you'd think, as long as you have other nukes, slows, and debuffs on your team. It depends on team compositions and lane assignments, though. If I am sharing a lane I'm far more likely to stay with a traditional Assassin build.
I'll keep my eyes out for a solid replay of hybrid Oak in a 3v3 and post it here when I find one.