I've never been in the townhomes. I just thought it might be a better option than 2 AS rooms. Sorry.
Well, if those are the two choices, the townhome will absolutely be more comfortable. But, I'd go with a 4BR instead. It wouldn't be that much more expensive, but would fit the travel party much better.
The question of onsite or off is one that has no single answer. Everyone must decide for themselves whether the onsite premium in dollars is worth the (tangible and intangible) benefits. Different people will value those differently, and so different people will come to different conclusions.
I enjoy my onsite stays, and do think they bring additional value. But they come by virtue of exchanging other (much less expensive) timeshare weeks into DVC---it costs about the same for me to stay in a DVC unit as it does to use my Wyndham points to stay at Bonnet Creek. While that's true, staying onsite is a no-brainer for me, because while Bonnet Creek is lovely and sits in an excellent location, being in a Disney resort does add value.
If, for some reason, those DVC exchanges were no longer possible---a very real possibility---I'd rather just stay at Bonnet Creek than spend the additional money to stay onsite.
The difference in cost between a 2BR in Bonnet Creek and a 2BR at OKW rented from an owner would be at least $1500, and that's more than being onsite is worth to me. It's less than being onsite is worth to others, though, and that's why Baskin Robins has 31 flavors.