pasoundman
A "locked out " reverser really is not a massive issue.
We don't even consider the retardation effect of reverse thrust if we are using a dry runway for takeoff, and even on an aircraft like the 747, which I guess has far more potential for assymetric thrust handling issues than an MD, we on occasions operate with one reverser locked out, even an outboard one. It does lower our landing cross wind limit and you are aware that the aircraft is slightly assymetric when reverse is applied but a correctly locked out reverser it really isn't a significant issue.
(edited to add that fireflybob beat me to it)