Today, I decided to try creating an "emergency" MainStage concert using only plugins in the event that my main live rig stops working for some reason.
My approach was to create a basic set of instruments and put them in an "Instruments" set.
I then created a new set with patches for each song and inserted aliases from the "Instruments" set so that I could keep memory requirements down.
Here are the issues (and also some suggestions for consideration) I ran into while doing this:
1) After setting up a keyboard (an Akai MPK 88) in Layout mode, the "learn lowest key" would not in fact learn the lowest key. I had to do it manually.
2) I pasted a channel as an alias. I then deleted the alias and pasted an actual channel strip. From that point on, it was impossible to get sound out of any plugin that I inserted into that channel strip. I could open the plugin (tried various different ones) and those that had audio output meters did indeed show that they were responding to the keyboard and generating audio, but the audio didn't make it into the channel strip. I had to delete the actual patch and recreate it. I was able to reproduce this twice.
3) It doesn't seem to be possible to paste an alias to a channel strip more than once in a patch. This is a real pity --- there are several places where I would like to have the same sound be produced twice, with one transposed up or down an octave.
4) When you leave the Layer Editor to go to another tab, the "Learn lowest or highest note" buttons should be turned off if they are on. I got bitten quite a few times as I flipped from the Layer Editor to the MIDI input tab as I was configuring multiple layers only to discover that keys were still being learned.
5) There needs to be a way to resend all the initial program changes (including bank select and initial CC values) for a patch without having to leave the patch and come back to it. This is a real pain
6) I'm not sure if I'm missing something but if the patch list view is longer than what will fit on the screen, I could not find a way to scroll to the patch I want. I had to click on a patch near the bottom of the screen which then scolled the patch list up so that I could find the patch I needed.
7) There should be a way to show ONLY the patches for a selected set. That way, it is far less likely that the patch list will exceed the vertical available space.
Some of the above are nuisance issues but clearly bugs (like #2) but #5 and #6 impact performance mode.