I think the default system is better than people give it credit for. Are there issues I have with it? Certainly. However, many of the issues -such as weirdly worded spells- are easy to fix (for example, Sunbolt should not do impaling damage.) A few issues are more problematic, but even the most severe problems pale in comparison to some of the issues I've had with magic in some d20 games.
That being said, I've heard really good things about Ritual Path Magic. I haven't yet tried it myself, but, at some point, I would like to.