I don't undertsand why you would want to create a completely new client for this. It would be far easier (though still complex) to just convert the Ages from Uru:CC to be usable in MO:UL, instead of writing a new client.
Why build a client that's exactly the same as MO:UL (with the old Ages) when we have MO:UL?
Are you a programmer? If you are, feel free to try... but remember Plasma took years to develop, and that PlasmaClient (the only program I know of as an alternative to Plasma) was still very incomplete when it was shut down.
In any case, I doubt this would motivate Cyan to make new content - simply because Cyan CAN'T. They just don't have the money for it.