I think thats because of the abundance of good talents low in the trees that are, nevertheless in like tier two of stuff which means you have to choose (why that aim buff is in tier 2 of the tanking tree I'll never know).
Still less of a variance seems to indicate that it doesn't really matter (which to be fair was almost always the case. In classes without a main stat buff talent it was always about 1% crit for about 5 total bonus damage).
Still I'd like to know more about your testing if you don't mind. What'd you try what were the results etc. PM me if you get bored and can spare the time?
Check edit... I went into some more detail about the root of why I think it's better. I can shoot ya my TS info as well... prob not gonna be on until late tonight and will be on less in the next few weeks. (getting married friday)
But in the end... I noticed that when tech damage went up my over all damage went up significantly.... when another guildie broke it down in the same way I did... it actually makes a lot of sense.
But like many I was too concentrated on my rail shot damage which is a waste of stats IMO.