I asked the same question in the last week of March when Dish lit up the Austin HD Locals on 61.5 - should I add a wing dish for 61.5 or wait for the imminent roll out of the Eastern Arc that would only require a single dish? The sage advice at that time was to wait, since EA would be up "soon".
But then AMC -14 didn't make it into orbit and Dish fell back on Plan B -- Recycling Space Junk
A lot can still go wrong, moving two old sats into position, etc.. And then there is the issue that EA is supposed to be exclusively for NEW subs for a while.
You'll have to make your own choice. But I'm very glad I had Dish install the wing dish back in March and did not wait for the fabled EA
Talon Dancer