Nonetheless, it just means you will have a one-two punch in terms of coverage. No matter if Cricket opens large or small, there will still be that Metro service backing their customers up, and vice versa. This is just a way to sell more phones and get more customers, so it's business as usual.
I personally think it's a win-win situation for customers in an area equipped with both Metro and Cricket after the 10-year partnership agreement.
If the two companies do eventually merge, which is most likely going to happen in order to stay competitive with other carriers, they will just sell off the extra bandwidth. T-mobile will most likely gobble it up, even in the future, to expand their AWS footprint for their 3G.