Bloomberg Businessweek has an informative (if somewhat fawning) piece on T-Mobile CEO John Legere that documents the carrier’s “wacky plan to trash the wireless business model.” The nation’s fourth-largest carrier has made some bold moves in the last year or two, as the piece notes, including eliminating handset subsidies, two-year contracts and steep international roaming fees, and recently offering some free data to tablet users. And in a few cases, it has forced the bigger tier-ones to follow suit.

Those recent initiatives seem to be paying dividends, too. T-Mobile recently posted its largest quarterly growth in four years, adding 1.1 million customers (including 685,000 postpaid users) and boosting revenue 27.5 percent year-over-year.

I’m not all that surprised in T-Mobile’s recent traction — like some other analysts, I believe the smaller tier-ones have a chance to compete more effectively on price and services now that their 4G build-outs are catching up to Verizon and AT&T. But one looming question is whether Sprint can take advantage of these market factors and close ground on the nation’s two largest carriers. Sprint said this week that it lost 360,000 net customers during the most recent quarter and it suffered an operating loss of $398 million.

There are some good reasons to believe Sprint can turn things around in a hurry — the shutdown of the Nextel network is complete, the SoftBank investment will provide plenty of cash and it just launched an impressive new LTE network — but the carrier will likely have to take a page from T-Mobile’s playbook and come up with some innovative new strategies to threaten the AT&T/Verizon duopoly.