*shrug*
It's a fair limitation. Ashikaga isn't a massive powerhouse, especially in the more recent Versions with stats toned down from the original. Their units aren't all that heavily armored, either, IIRC; good but not great. The base morale can be nice (although it might mean greater losses in a bad defeat since they might wait longer to break), and the bows are spiffy.
The Jonin having water magic gives them the unusual ability to be assassins with amphibious capability (so long as they're not feebleminded) in addition to the more obvious quickness; might be the only ones except R'lyeh star children to offer this. Intriguing.
As for Bane Spiders, I have a certain perverse fondness for Bane Spider prophets.