I would say it's a good mobile rig if used with the good interface. Theoretically in a near future the thunderport will solve all issue, and for basic mixing, recording or editing it is more than enough.
As a main rig though, I would second the fact it lacks ports and a few ghz.
That said, I have the exact same ports configuration on a MacBook Pro 15 and I don't see why it would limit me. A dongle, an interface, and the coreaudio engine is fast enough to be usable in an editing scenario (latency is good enough to not use an interface). I am myself waiting for a new apple display. They have to release a 4k thunderport display in a good price range.
I would advise to rely on an other main rig, any other mac computer would do, a powerful Mac mini is a cool solution nowadays.