Hi Stephen,
In my experience, the UI5 touch scrolling events work fine on iOS even within the DS SDK. However, you could have encountered an exception case or it may be related to the version of iOS you're testing on.
The only issues I've encountered so far are related to click events not being supported on the desktop, as discussed in the other comments in this thread.
On a side note, after checking again, the UI5 bug I was referring to with the sap.m.ScrollContainer actually relates to horizontal scrolling, as can be replicated from the following standard demokit samples:
UI5 1.18.12 Scroll Container (Horizontal scrollbar missing)
UI5 1.20.6 (Horizontal scrollbar works correctly)
Regards,
Mustafa.