I'm ready for what comes next after Agile.
  I've been through about 5 Agile shops now. I would say 
  one of the 5 ran Agile well, the rest were a mess that
  just makes it frustrating for everyone.

I can't tell you what will come after agile, but I can tell you that it'll probably have around a 20% effective rate all the same.

Also there's nothing in agile that would prevent you from designing things upfront, I believe the exact phrasing is "Responding to Change Over Following a Plan". I.e., build extendable / adaptable designs (that can change), do the amount of specification upfront that provides value, but don't ticket-plan 2 years of development upfront.