I imagine the reason why it sounds degraded when putting the looper at the beginning of the path is that the signal chain is then having to deal with more one than one layer of guitar, not something amps are typically meant for or good at. But it does sound much less desirable than it should when using the looper at the beginning of the signal chain even on low low gain chains that shouldn't be causing any dramatic compression. I do think there is a problem that needs addressing there.