I am working on two bigger projects, both with meteor/mantra/react. Mantra tells you perfectly, how you can embrace a component-driven design and react is definitly the better tool for this approach, than blaze. It sometimes scares me as well, how different it is than the classical meteor way, its also much more verbose. But it gives you also so much more power and control, so that - at least for me and my team - , this is definitly the way to go (for now).
Pub/Sub is the only thing, that doesn't really fit well anymore. I'm therefore desperately looking forward to Apollo!
I also have some blaze apps and I love blaze for its simplicity, but they only require little maintenance and i am pretty sure that blaze will work as long as these applications are alive. I am glad to see it in good hands with @mitar.