This. If there are deficiencies in the code base, focus on those, their effects, and the gains from fixing them. Blaming people is rarely a good idea, for many reasons.

If the original dev worked on the code base for a long time, they're probably already aware of them. God knows I'm all too aware of the deficiencies in code I wrote years ago, but that's frequently how things look after years of updates and feature creep. Everyone on our team has code like that, and when new guys come in and point them out, we just sigh and say "yeah it would be great to rewrite that knowing what we know today". But budgeting time for that is not easy.

Edit: Also, like others said, I think you need to adjust your expectations. Working with code like that is life, and you should appreciate the fact that you, with your outside perspective and youthful energy can make a change for the better. But it's going to involve lots of refactoring and test writing.

The "Legacy Code" book referenced in another post is a great overview of this. I'd say of all programming books I've read, it's one of the ones that are most relevant to my day to day work.