I just wish it wasn't so tightly integrated into everything. I'd love to use Meteor as a library, but I'm always afraid of choosing something that I can't replace later.
You could always use the DDP library [1] ("REST for websockets") for realtime transfer. It's separate from the "core" Meteor package (a collection of packages, really).
There's also a list of libraries for other languages that communicate with Meteor via DDP. [2]
There's also a list of libraries for other languages that communicate with Meteor via DDP. [2]
[1] https://www.meteor.com/ddp [2] http://meteorpedia.com/read/DDP_Clients