If they wanted to go overboard, they could allow parallel paths as well to simulate running 2 different amps in parallel.
Did some profiling last night with my other guitarist and his Orange AD140. We both talked about how useful it would actually be to run 2 profiles simultaneously since we would wind up with a profile that did 1 thing we liked but lacked another, then make some adjustments and get the thing it lacked, but then lost the aspect we liked about the previous profile. Being able to run both would have allowed for a fuller sound that we couldn't quite accomplish at the time and would have been fun to experiment with.
I know the Pod could run two amps at the same time. Don't know if any of the rest of their reincarnations up to Helix does it? I suppose Fractal doens't do it?
Fractal and Helix can absolutely run 2 amps and 2 cabs simultaneously. It's part of the reason Kemper users here have brought it up a number of times on their wishlist, especially those migrating from Fractal products. Some dismiss this as not something many people want, but I absolutely think people would use and experiment with. if given the option.