[Squirrelloid]

First of all, for raiding you aren't going to be fighting 10 knights, but whatever random PD is. A bane with brand and shield is plenty sufficient for doing so.

Walking and non-stealthy is perfectly acceptable for at least some of your thugs, because they won't be able to protect everywhere with an army. That's why thugs are cheap and spammable - you're trying to avoid serious resistance and simply take lots of provinces.

If you need more mobility, boots of flying gives it to you and the total gem cost is still less than what you're putting on your wardens. Boots of quickness are better if you don't need the mobility.

Banelords are a step up and make good anti-thugs as well. I've watched banelords clobber Vanjarls frequently.

Appropriate shields are vine or gold, although eye shield works for strictly anti-thug duties and there are a couple of others that would be acceptable. But almost any shield can do the job if its just raiding PD.

Bane advantages:
-good armor
-decent hp (20, and more than twice that for banelords)
-0 enc
-chill aura
-CR100/PR100 built in

In addition to their virtues as raiders, they also gear up well for anti-thugging or army support. FR100 can be achieved by using fire brands instead of frost and a dragon helm. SR100 can be achieved via ring or copper plate. Lucky pendant can always be added. 2 logical boot choices exist which increase their effectiveness substantially. None of this is necessary for raiding though, and even in an army support role you'd want to expend as few gems as necessary to achieve your goals.

tldr; people love banes because they're cheap for what they can do.

-----------------------
Castellans might be cheaper than indie commanders, but you usually build forts until you can spend all your money on mages every turn. And by the time you can't build a mage in every fort, you're no longer using troops the Castellan can lead. Regular leadership loses usefulness as the game goes on for most nations.