Depending on how many points you are playing with is what matters. In a 1000 point list, I would say no because those 50 points will be lost quickly with hullpoints. Stick with cheaper units (What IG is best known for!)
If you are paying 1850 games, then I would throw him on either a punisher or an executioner. The punisher is great against monstrous creatures and it will be good against fliers since pask adds a plus 1 to pens and rerolls against MCs. The exec with pask is iffy, but with the plasma cannons essentially being ST8 on vehicles, it can be scary to throw 5 of those blasts at a transport with bs 4.
Truly, a vanquisher is a bit outclassed by vendettas and their twin linked lascannons. Ya the 72" melta is great, but using all those points on a 1 shot bs4 is scary. Especially when the 205 points can buy a vendetta and HWS with autos. I've had my vanquishers miss every turn. Sometimes I want to cry.
Don't forget that the Leman BT turret is ordnance, so you can roll two and pick the highest when rolling for pen, and the blast isn't halved anymore in 6th ed. So for cheaper the BT is more reliable.
In short, Pask is awesome when used in larger games, but in smaller games he costs too much.
Dear Lord the IG has tons of Dakka