Well, Lionel is the folks that can address low output of the Legacy base. If you know someone with a 'scope, you can measure the output objectively.
I thought to further this discussion, I'd post a few waveforms that illustrate how I tested and why I felt the signal generator was a suitable replacement for the command base to test the buffers.
As you can see, all of the bases and my test generator put out a similar clean waveform.