The power. Not the discipline. The discipline, I'm well aware has some potent abilities, but with regards to the power Telekinesis itself I'm wondering if I'm missing something.

As far as I can see, Telekinesis is completely and utterly inferior to Spectral Hands. Spectral Hands has a strength equal to your willpower, and looking at the "lifting/pushing/etc." at practically every level of WPB Spectral Hands would be able to lift more than Telekinesis.

It's also got a lower threshold and superior range. Neither have any overbleed.

Am I missing something here, or is Telekinesis completely inferior to a minor power?

yeah lol
never really noticed this, but it is very true....
you only gain a .5 kg weight bonus per point of willpower from telekinesis in terms of lifting....
this seems a very silly trade-off for higher threshold, lower range and the fact that you have to take it as a major power...
I guess the only difference is that it is a half action focus rather then full, and if you got discipline mastery it would have 4 lower threshold, however this seems utterly worthless considering how rare major powers are for psykers.
That is a pretty sad realization....
oh well, guess this is why house rules are important

Yeah. The same is unfortunately true of Precognitive Dodge, which is also a power which seems sadly underpowered compared to its much more useful little sibling Distort Vision.

I have read the Errata, but even in its nerfed state, the minor power is cheaper, better and more versatile than the more expensive discipline power.

Telekinesis is a sustained action. Spectral Hands is not. With Telekinesis, as long as you keep it switched on, you can levitate that object for as long as you like (until you have to roll to sustain it, as per Sustained rules) - Spectral Hands is pretty volatile and you have to manifest it every round, and a round is only a few seconds of real time. Good for pulling a lever or something, not great for moving a vase across a large room.

As for the lack of overbleed: discuss it with your GM and see if you can House Rule it