You shouldn't ever really be using Tank Commanders. They can only issue orders to their squadron, IIRC, and cost so damn much. They're only there for rule of cool, but anything attempting competitiveness shouldn't really be concerned with that.
I think that Pask is extremely viable, and Tank Commanders in general are still quite good (at least at this early stage). AV14 is pretty good for your Warlord, he boosts his tank's effectiveness quite nicely (mainly the dakka ones rather than the blasty ones, but since they're all so much cheaper while the Battle Tank remained the same price I guess that's what your were gunning for anyway), and if you don't need the infantry orders that much (if you're running a super Blob Squad with Priest and Inquisitor, for example), you could do a lot worse than the Tank Commanders.