Agree, this will not be the only time we will see this.
They will test it here and see how many fight over it, then they will release it as a 3rd place prize and watch the money roll in. For all we know they might and probably will release this mod several times and there might be someone out there who can upgrade 4 builds at once.
Honestly, how could you possibly think this is the only time you will see this, like it will never be released again!?!?!
If you haven't realized it by now gree only cares about the dollars and as TZora said, this is their trump card and will milk it for all it's worth, which is a lot to most.