Frege's views seem to have crazy results, yes. But if we look back in time to the pre-Kripkean philosophers, we can see that there is lots of craziness. Frege may have a structured account of propositions and of thought, but he seems to have the same craziness.
Let me pick on Santayana, since he as much as anyone is a good candidate for being a 'Locke-Plato,' as Sellars calls them. Santayana holds roughly:
1. The only meaningful language is private language.
2. Knowledge is just faith mediated by symbols.
3. Intuition is direct access to Universals.
Givenness is super important for Santayana. The Given from sensation, and from thought.
The philosopher's aim, for Santayana, is just to have an aesthetic experience with contemplation. It's fun to ponder the Universal triangularity. Life is crappy and unhappy, but the life of reason offers some escape. The Indian mystics are pretty good, but the Greek notion of cultivating a higher man is a better notion.
Right. So this is crazy. But consider the problems we though Frege faced today. Santayana thinks that the only meaningful language is my language. So he'd be an individualist about senses. When other people make noises, I only understand what I hear; my meanings are used. But usually I just behavioristicly respond in animal faith.
Now I can have all sorts of wrong descriptions of people, so I may think that I am thinking about Einstein but really am thinking about the inventor of the atomic bomb, whoever that is. But this is just a case of non-thinking! This is just me dumbly using symbols governed by animal faith.
So even when I think I'm thinking, I'm not. The real Thinking is the intuiting Universals bit. I am Given Universals in experience or Thought. But I can bumble around in animal faith making squeaks and squawks and what have you. That doesn't bother Santayana. Real Thinking, not animal thinking, is hard to do. Most people never do it because they are clouded by animal faith.
It strikes me that Frege is a sort of bridge away from some poor Platonism combined with an unstructured view of propositions and thinking. And strange other views. But an old-school philosopher (pre-Kripkean) might not see anything wrong with that. We might take these aspects of Frege as a reductio against him, but people with the 'right' intuitions I don't think would be bothered at all.
The history here is interesting to me.