The time for a merger was before TMUS made all their upgrades and bought AWS3 spectrum. I just can't see it making financial sense now, even if the political winds change. The window for that has passed for the next 4-5 years. Frankly, unless Dish decides to enter the market as a 5th carrier (or does it in combination with Google), I don't see the FCC letting any of the big 4 merge. The only way we get to three will be if one goes bankrupt.
I predict Sprint WILL participate in the 600 Mhz auctions with its partners (Shentel, RRPP), unless the FCC decides to completely neuter the reserved spectrum requirements. I think this talk from big E is just Sprint making it clear that it can't and won't pay the "arm and a leg" prices you just saw in the AWS3 auctions. The more expensive the 600Mhz spectrum becomes, the less it becomes economically advantageous versus increasing your site density. The economics of this will vary from market to market. In places where the RRPP partner has the 700Mhz A block license, plus the 5x5 band 26 spectrum from Sprint, I can actually see them not willing to pay much at all.