I quoted HHs post. Something has changed. Something radical. The airline was sold. The new owner is planning on positioning the airline in the image of Spirit airlines. I would venture a dramatic difference between the new Frontier Airline vs United Alaska etc.
I don't know how much of the changes will be implemented by July.
But, and here is THE THING...
You could say that about any airline. Any of them could (and probably are) planning changes in the coming months. Just because some company EXEC says something, does not really mean a heck of a lot....spouting off, trial balloon, bad mood, tentative plans that are not really set in stone -- or even real plans...what do you really know?
They may be for the better. They may be for the worst, or they may not make much difference. Frontier may stop giving out bags of "peanuts." Do I care if they do? Not really.
They may decide to change seating -- if so -- while that may not meet my needs, that is something that takes a significant amount of time to accomplish and I seriously doubt it would be done by any significant percentage by summer (I fly with them in two weeks, if they have doubled the number of cabin seats, I will let you know

)
So, for any serious change to affect the OP, I seriously doubt it. Already bought the ticket? If so, immune to any fee "bites" and that is the only real "possibility" at the moment for the OP.
Yes, as I said, they could implement some serious changes -- and as I said -- so could United, Delta, etal.
With the American public complaining loudly and widely about airfares, it would almost be counterintuitive for airlines NOT to take "cuts" in service as far as the market "will bear" in search of greater market share.
The test comes when the public rebels (and we have already seen that in other fare models).
Anyway, when United tells me I have to share my row with a crate of turkeys, that's when I protest (....wait, has not that already happened?

)