Jiriki's already declared that there's not such thing as 'true information'.
He's tried to explain to you how regardless of your fragging, each action (whether it be spores, tanking, baiting) will influence the result towards either a win or a loss and so it will be included in the trueskill system.
It an imperfect model that makes a very good attempt at mathematically portraying overall skill.
The beauty of Jiriki's system is that it will take into account all of the unquantifiable actions that you're moaning about. He's explained why to you already, and very eloquently too I might add. As someone who lead my team, motivated my team and did all the shitty jobs for my team I can still relatively comfortably say that my input can be mathematically taken into account using the win/loss, player to player system that he's described to you.
It's very daunting and, not being a maths student, I won't even begin to comprehend the details but I can theoretically agree that it's possible. I know that you're thinking "wtf, how can he measure the fact that I did this!?" but this is an area where you won't ever understand the actual mechanics and just have to sensibly evaluate the results and concede that there are people that a very clever - much more clever than you! Jiriki put forward the results and they are overwhelmingly compelling and "only a fool" can ignore them. I'd like to hear your response to the results directly, in fact.
Actions can be measured. Psychology does use statistics to measure the likelihood of Bob wanting to kill himself. The stock market is approaced mathematically and the maths is used alongside a degree of human judgement and reflection to make an even more accurate assessment. Economics, itself, is a whole subject dedicated to quantifying behaviours and measuring trends. Whether trueskill is 99% accurate or 60% accurate, it can still be used alongside your own personal feelings to make a further informed decision. A problem only technically arises where the system is less than 51% accurate (though I would say the 'acceptable' level of accuracy is much higher).
I'd also like to add that some roles are more important and though a player might be equally amazing at gorging as another is at fading, the value of the player relative to the outcome of the loss is what is most important. That amazing fade has more value than that amazing gorge and so I think you should see it less as a measurement of skill and more as a measurement of value. The likelihood, at the end of the day, is that the amazing gorge will be recognised as such and recruited duly. If he declines, then perhaps the system will have been offered an imperfection but the system doesn't claim to evaluate perfectly, it claims to offer the probability of a player being of a certain value. In the common case of having a player who is an adept fade go skulk, his value is still measured by his participation in the win. A team would only be using him if his value to the team was significant, otherwise he would be sat and not played at all.
There are a million little examples that you could put forward in an attempt to undermine the working effectiveness of the system and to every example the answer would be the same; that the system only measures the probability that a player is valuable and that if a player makes a sacrificial decision that is beneficial to the team, the action will be taken into account no matter how intangible.
I'm still not sure if I'd like an accurate ranking of skill though anyway. I like the dynamic of finding a player and measuring his worth through your own eyes.