If you are certain that the old growth is truly dead then removing it is a good step.

Blueberries are pretty resilient, so if it has anything that looks healthy, it will probably be just fine. As far as pruning, you might want to check here. If you scroll down, it talks about pruning and what to prune to get best results. If the bush is mature, you may well have some canes that are pretty old (in blueberry terms, at least).

Being vicious isn't necessarily a bad thing for the bush. Blueberries want to have air through them, and they want to be pruned pretty much every year when they're mature. You're probably pretty safe cutting them out if you don't think they look good.

I had to prune out some pretty good looking branches from one of mine this year to give better shape and air flow. My general rules of pruning for everything are to always prune out things that are dead, broken, or rubbing, and then for things that are occupying the same space or are too dense I stake to pull branches into hole and prune out the weaker or less productive of redundant branches.