There has been continued speculation over the past weeks that Sprint is about to make a bid for T-Mobile. Most of the discussion has centered on the possibility to create a "strong third carrier" in the US market. While I understand the motivation for this from the perspective of protecting margins and decreasing the competitive pressure in the US wireless market, I offer a complimentary strategy for this kind of merger, if the rumors are true.
Maybe Softbank has realized that the Sprint/Clearwire network is a mess and that no amount of "network vision" is going to make it competitive. Sprint does not have a stellar reputation for network integration and overhauls after the Nextel debacle. Maybe Softbank feels nothing has changed. I think it is probably unlikely to be the top reason for Softbank to pursue this merger immediately after taking control of Sprint and Clearwire but it could be up there.
T-Mobile has been very successful transforming their network from a 2G network with limited options after the failed AT&T merger, to a high-speed 4G/4G LTE network by refarming spectrum, taking over regional carriers etc.
If this indeed is part of the Softbank plan, you should not be too surprised to see the Sprint network go into a very early retirement if this deal closes. This kind of scenario would also make Softbank's US networks compatible with their Japanese networks which just like T-Mobile are HSPA based (for 3G).
Of course, there is another option that can achieve the same result and have a much greater chance of passing regulatory muster. Sprint and T-Mobile can decide to share their networks (close the Sprint network and build on T-Mobile) but continue to operate as separate brands and companies. This is done all over the world, just not in the US.