Since our computing power is being used for something useful, the competition is welcome! The influx of new miners will hopefully keep coming steadily so this coin can build some serious traction on the crypto scene, it's definitely going the right way. A falling payout rate for your hardware is something every crypto has, so it's not really unique, and I wouldn't consider it a problem, as long as the value of GRC keeps climbing, which it most definitely will if this trend sticks.
So I guess we should just give a hearty warm welcome to all the new BOINCers joining our awesome community! :)