Re: MCU Phase 3: Have it your way
I think Avengers will be a solid trilogy, 4 if you count a two-parter (damm thats a cool idea.) but after that it might be put on the back burner a while. Make a bunch of character movies that take people's minds off of RDJ and Tom Hiddleston and whoever else blows us away in the next 6 years.
They may have been thinking very long term when they wanted Galactus/Surfer back. I mean, after Avengers 3, if you pile together some new names (Strange, Namor or Fantastic Four) you practically got a whole new MCU for a while. Until they find a worthy successor to the core four.