Well, sort of. Series instead of parallel trades one problem for another. The higher net impedance is much less likely to send an amp into instability, yes, but you're still limited by the amp's ability to produce clean power, so your practical sound level limit is about the same. With parallel you'll pop fuses or get voltage droop as you pull too much current. Series, the amp will clip when you hit the voltage rails. I'm not sure which is worse.

Assuming you've got plenty of power, you'll still get lopsided power delivery if the speaker impedances are different. In parallel, the low impedance speaker will be louder; for series the reverse is true. I still think you'll get best results with one channel == one speaker without knowing more about the nature of the loads.