If Melnyk is providing his v-e-r-r-r-y deep pockets and high local levels of credibility to ensure the survival of the team for at least five years, there's a decent chance an Ottawa team could work. Rivalries with Toronto and Montreal would certainly spark interest. A grass pitch would work to attract some higher-profile Canadian players.
The Saputo stadium, even BMO Field, are perfect examples of how suitable stadia can be built quickly and at relatively low cost. Melnyk might be competitively-minded enough to not want to let Jeff Hunt and Co. have clear sailing in a relatively good marketplace with a revivied CFL team.
A pre-emptive move by Melnyk and MLS might prove shrewd long-term strategic thinking since the CFL owners will have much shorter pockets and an audience or media unlikely to have much patience with a struggling operation, especially one with stadium issues causing uncertainity. Luring away a small percentage of sponsors or corporate support might be enough to tip the scales against the CFL.
Don't overlook the possibility of gov't money joining the process in building the stadium. Ottawa is, after all, a rather international place. I can picture a gang of cute U-11 all-stars from Nepean showing up on the doorsteps of the embassies selling season ticket subscriptions like they were Girl Guide cookies.
I've got family in Gatineau, across the river, and everyone follows soccer. The kids all play it. With Melnyk on board, I'd bet a lot more people than some think would buy into an Ottawa franchise. Just look what happened the minute deep-pocketed, experienced ownership bought the first Canadian franchise.