Hello,

Yari ashigaru in SP? I frequently use them, up to 50% when playing Oda. They're cheap and fast, not totally worthless and indeed quite good when having a few upgrades. Not everyone is going to agree with me, but due to the system they can become the most allround, cost effective unit available. There are some drawbacks, but you need great skill/luck to beat it.

AdrianII. It was Oda's general Toyotomi Hideyoshi who was ashigaru. He climbed the ladder and finally became Taiko (only nobility could get the shogun title iirc). Sort of an American dream in Medieval Japan :)