I agree that Ambiance shortcut with side swipes is a waste of useful and easy gestures. One does not change profiles every 30 seconds, and Ambiance can already be changed quite easily from the pulley menu (which seems much more convenient for that).To me, it looks like Ambiance was chosen for this side swipe because nothing more important to the UI was necessary: core functions are already covered by the up/down swipes and the side swipes from application view.

What I'd lke is to use side swipes in the multitask view to show more than 9 apps. Just like the N9 has a vertical scroll in this view, the Jolla could have multiple pages horizontally arranged (with the Sailfish dots on top to indicate which page is being shown).

The maximum of 9 covers shown is an old concern about Sailfish and Jolla sailors have often argued that 9 is most often more than necessary, that they usually use less than that. They also added that anyway it's easy to see from icons which apps are open but not shown as covers (well, I'd like to see a screenshot of that by the way to see how the icon is altered to show an app is open but not previewed in a cover). Yet, the large majority of the videos we see since November 27th show Jollas with 9 covers shown. It means that people do use 9 apps simultaneously (or more), or at least they want to keep them open. To be honest I'm not surprised at all because I often have in between 8 and 11 apps open on my N9 despite its more limited hardware.

tl;dr
Give us horizontally arranged pages of the multitask view so that we can side swipe from it to show more than 9 covers. Ambiance may be useful, but not to the point to access it with the two most easy to perform gestures. Pulley menu is perfectly appropriate for it.

Yes, turning pages with swipes from outside the screen might be confounding considering in apps we turn pages from the inside, but it's definitely worth it.

Hope some Jolla or community dev agree, and find a way to achieve these two challenges: multiple pages in multitask view, and side swipes to turn pages instead of accessing Ambiances.