While RT-fMRI is an incremental technological advance (it's just faster data collection with some spiffy signal processing) it hugely broadens the scope of fMRI's usability. The hemodynamic delays of traditional fMRI are atrocious. For the first time fMRI is giving us access to
when brain activity happens, which is nearly as importnat as knowing
where. If you look at the biofeedback work being done with RT-fMRI you'll see it's extremely exciting.
Also, I don't view the depth restriction of EROS as a very big problem. There are enough mysteries lurking in the top 3 centimeters of your brain to keep academia busy for a hundred years.