Which unit type do you miss in 40k?

[TheBearminator]

Are there any type of unit you would like to add to the 40k game? I know several unit types that I think are badly implemented in the game (you may have read me whining about snipers in another thread just a few hours ago for example). But now I wonder if there's anything you think are missing?

I can come upp with one. Fast walkers. Think of a lighter armoured and more agile looking dreadnought (preferably something with legs longer than a gretchin's) rushing att the enemy. Doesn't have to be as fast as a bike but perhaps with movement 6+d6 or something. I would love that.

Come to think of it. Why haven't we got walkers (or monstrous creatures) as transports? I can't be the first who had that idea.