Keep in mind, this is what the QoT can skill after she improved her shamblers 3 times and it has absolutely nothing to do with her shamblers, which is unique for this kind of skills and that's just very strange.
Not that I disagree with your overall conclusions, Tribue is a horrible skill, but this statement (that it's unique in that it has nothing to do with the skill points leading up to it) is not true.
Regulus' Dead Eye has nothing to do with Snipe
UB's Acclimation has nothing to do with Inner Beast
TB's Inspirational Flame has nothing to do with Circle of Fire
Erebus's Bloody Haze has nothing to do with Mist (though at least in this case, it's a defensive skill from a line of defensive skills)