Let's go over some facts:
1. I'm opposed to this acquisition. Mostly. But...
2. AT&T on the LTE side synergizes with CricKet, because CricKet has a fair amount of AWS spectrum. AT&T needs that AWS spectrum to make putting LTE in AWS worthwhile. AT&T needs LTE in AWS because their 700MHz holdings are, unlike Verizon, not nationwide.
3. CricKet LTE phones support PCS and AWS bands. Probably PCS A-F though. So you don't necessarily need to keep CricKet's AWS network running if you're Sprint and you buy them. Though you would need to add an LTE carrier below PCS G (not too difficult) to shut things down.
The CricKet purchase by AT&T goes to the almost exact same tune as T-Metro. Except AT&T doesn't need a way to make its stock public, and network synergies aren't nearly as much there. The 2G/3G tech is incompatible, but all AT&T has to do is rebrand its AiO service (or push people to AiO) and people will leave CDMA for WCDMA phones pretty quickly. The 4G tech is compatible...all AT&T LTE phones support band 4, but no CricKet phones support 700MHz of any kind. And AT&T doesn't have much AWS LTE at this point. Which means that CricKet LTE will stick around, unchanged, for awhile.
So...maybe there's less network synergy than I thought. We aren't talking Nextel here, but at this point on AT&T's side it's not too far away. And, no matter what, CricKet LTE phones will have less coverage than AT&T LTE phones on the merged network.
If I were AT&T, despite all of the above, I'd deploy AWS LTE on every site I could within the CricKet market in advance of the transaction being approved. Or PCS LTE, since some of my phones support that. And then bite the bullet and pay MVNO rates to Sprint or Verizon in exchange for shutting down the CDMA network earlier, because I need the spectrum worse than T-Mobile does.
All that said, I hope that, at least, the transaction gets slapped with a requirement that AT&T sell off much/most/all of CricKet's PCS spectrum. CricKet has enough AWS to still make the transaction worth AT&T's while, and AT&T can sell the PCS on the condition that the buyer continue to operate a CDMA network in the band (though maybe not that block) to they can get legacy CricKet roaming for free (again, so they can shut down CricKet's network sooner). One thing's for sure: this transaction, even if it's relatively small, shouldn't be allowed to just pass through because it's just strengthening the trending-toward-duopoly in US wireless.
So let's say the deal doesn't go through. CricKet will immediately look for Sprint, T-Mobile or Verizon to pick it up. Verizon doesn't really want CricKet, so they're out...probably. T-Mobile wants CricKet, but probably can't afford the price at this point, though they've certainly got the ability to migrate customers (they're doing it already with MetroPCS). But the concentration of spectrum at that point might cause some FCC consternation...maybe a PCS selloff to Sprint would be in order. Sprint, as I've mentioned before, could buy CricKet, spin off its AWS spectrum to T-Mobile, add an LTE carrier in PCS A-F in CricKet markets, then take CricKet's network offline market by market in favor of Sprint native with a PRL change or two. They might have to wait a year or two before there's 5x5 available for LTE in PCS A-F in some markets if CricKet is AWS-only in those markets (e.g. Las Vegas and Chicago), and they may also need to wait until their network is broadcasting more LTE than CricKet's, but even with those caveats Sprint could probably shut down CricKet's own network and sell off the AWS in a shorter time frame than T-Mobile will take to digest MetroPCS.
Also, the point about AT&T trading Sprint's WCS for PCS is quite valid. Sprint doesn't have enough scale to realistically deploy something there, but AT&T does. Sprint needs all the PCS it can get, and AT&T doesn't quite as much. So maybe that's how a forced PCS divestiture goes if AT&T goes through with the transaction.
Lastly, mark my words, Sprint and T-Mobile will be one company three to five years from now. Probably including C-Spire, probably not including Ntelos (to Verizon), probably including part but not all of US Cellular (the rest will go to Verizon or maybe AT&T). Adding one LTE band to a phone (and that's all that would need to be done to gain network compatibility) isn't a big deal.
Though at that point...God forbid...all three big carriers would have LTE on PCS and AWS, meaning that they'd look downright silly if they didn't allow roaming on each other's LTE networks.