We've already heard Jim Ross commentary over MMA fights and even other soccer games, most prominently the Germany thrashing of Brazil in last year's World Cup. It turns out that Jim Ross commentary over any soccer game can be exciting though, as highlights of a Sporting Kansas City and FC Dallas were dubbed with the legend's commentary.
Now, if you want a way to make the MLS more popular, a good start would be to have JR calling the games. Imagine the southern flavor he could provide to fans looking for a way to make the game more relateable to them. At least then MLS would have better commentary than the WWE.