I personally think brushless will be the future for increased run times, multiple output settings (mod, stock, etc.) and virtually no maintenance (comm cutting, brush replacement, etc.) and it is ultimately cheaper (maintenance costs). Yet, it still has much room for improvement.
Overall though, I feel it needs to get more standardized so multiple manufacturers can make components instead of full systems ala Novak. This will allow specialists to more quickly refine and improve the technology which will make it more attractive to customers and more profitable for the companies.
This way Novak can focus on the ESC can come up with tighter tolerances, more adjustability, cooler running, whatever. And motor specialists can focus on making the motor better/more efficient, lighter, cheaper, whatever.
To get there though, we will need a standarized system like the brushed world has so everyone's components work together. One main company isn't going to be able to do it alone.
As far as "limiting" motor tunability -- how long have brushed motors been around, and how long has it taken them to get them to the current system of "tunability"? Imagine what could be done with that amount of time on BL systems. I think the same level of adjustability could be present -- although without having to buy countless sets of brushes and all the tools necessary to maintain a motor.
As far as the racing is concerned -- any restrictions will push the focus elsewhere. I personally would rather have that put on driving and setup skills than on motor tuning. For the meantime, why not allow both technologies in the same modified class? Who says it has to be one over the other? In modified, anything should go (that includes the body as well, but that's a different story...