I think the unit is fine. The devastating thing about it is the sheer amount of area it can saturate. The damage output is relatively spaced out in time though, so you do have the time for a quick retreat if you sense your in the center of it. Alternatively you do have the chance sometimes to quickly run perpendicular to the direction of the rockets and be safe.
One quick and smart flanking tactic can often spell the end for a katushya. 1 shreck volley, tank or AC raid spells the end for it often. Try pick an unexpected route and force a distraction somewhere if possible. Keep note if a player consistantly keeps them in the same position as this lets you plan for the offensive on it. Recon run and you will do this extremely easily.
As for hitting the base, I can't think of any 1v1 maps where Katushya can just sit in the base and fire volley at the enemy base from your own. You still have to bring it up to the center a bit. It does give you a chance to hit them if they try do this, but best thing is try avoid mass retreat.
The Calliope was more devasting and harder to kill in CoH1. More accurate (used aggressively), faster and more health. Yeah I know its doctrinal. Just try find them holes!