Double tap and hold option
I've tried several keyboard and mouse replacement apps and the single tap and hold to drag is always frustrating for me Since I like to rest my thumb on my phone when I'm not actively using it, a double tap and hold to drag option would be preferred.
Also, a single tap and hold should have an option to right click since I hold my phone with one hand making two finger taps and gestures extremely difficult.
Scrolling with a thumb is possible with a scroll zone at the edge of the screen. Gmote does all of this well but has other issues that make it less than ideal for controlling a pc.