The problem w/ Palm's WebOS devices to date has never been the OS itself, but the sub-par hardware that it was on. I think most people who have used all the major mobile OSes and WebOS would tell you WebOS does multi-tasking as well as, if not better than, Android, Blackberry, iOS, and Windows Mobile.
As for the "disappointing" Palm Pre 2, Palm/HP had tons of unused Pres that weren't selling, so they put in better processors and more RAM just to run out the supply. In addition, you can't expect a completely new device designed from the ground-up 3 months after the buy-out and, let's face it, Palm didn't have the money to be engineering a brand new device prior to the sale to HP, so that's what it would have had to have been. Outside of the keyboard on the Pre, which is average to frustrating, depending on the size of your thumbs, everything else is pretty decent now that the processor and RAM have been upgraded to competitive specs for an entry-level smartphone. I love the form factor of the Pre; it fits well in a shirt pocket unlike most smartphones.