Opa is neat, but the two license options of AGPL or "talk to us for a price" basically ensure it will never achieve anything close to mainstream usage.
Agreed. This 'but we wanna make millions with a dual license as that 0.000001% of open source products do' attitude is definitely the largest barrier for this. And it's incredibly short sighted; just open up (L)GPL and do services + support. All big companies WILL buy support as that's what they do. AGPL is crap and will stop your growth; you have an uphill battle already, so don't do stupid things like that.
All big companies WILL buy support as that's what they do.
No they won't. MIT license lets them use the software for free. Why woukd anyone pay anything if it can be used freely?