I've never played League of Lengends (LoL) or any of the DoTA spin-offs as they're not my genre of choice. (I.e. I SUCK at them.
Instead of the "hero rotation" in LoL it'd be more of a "when we release new mechs you can only get them with real cash for a number of weeks before you can buy them with in game money like normal."
So as an example:
New Mech comes out October 1st. Say the Stalker. The Stalker is available to everyone on October 1st IF they pay $5 to "unlock" it early. You'd still have to pay for it with in game funds you just paid for the right to buy it "early." Then say, November 1st they release the Urbanmech and once again for $5 you can unlock the Urbanmech right away and now everyone can purchase the Stalker with only in game funds.
This allows them to moneytize new mechs WITHOUT them being money only forever. It's a time lock preventing everyone from getting them right away unless they pay some real world money but eventually every mech would be purchasable with in game funds. OH, and with this compromise even with your $5 you still need your in game funds to buy the mech. (I.e. EXP/cash requirments the mech would have for everyone.) Hence the "lower" price of $5 versus the normal "premium" price of $10-50 bandied about.















