Not quite. A touchscreen can detect many fingers, that can do many gestures.
The problem is, exept zooming (pinching with 2 fingers) and moving around (swiping with 2 fingers) the potential is pretty much unused.
Intuitive (like swiping and pinching) is none of it though and it can only be useful once muscle memory kicks in. So I guess this is the reason, we do not have a global standard for anything advanced multitouch.
I think you're wrong. There are very few combinations available for things like text editing.
Well, people who played the violin or alike can do this, but yeah, it was hard work to learn and cannot be expected of the general user.
So yes, it cannot be anything complicated.
One of my ideas is to use the position of the fingers and the timing they touch. No matter which finger, what matters is the position they touch down relative to each other. So 2 (or 3) touches, like double click, but with 2 fingers and you evaluate the positions.
Simple variant: "pointing finger", "middle finger" -> one action (one touching point, then another touching point shortly afterwards left of the first touching point)
"middle finger", "pointing finger" -> another action (first touching point, then the other touching point to the left of the first one)
Or you can use the 2 thumbs, or thumb and pointing finger. And use up and down as well. So you have "middle" "up"; "middle" "down"; ...
And the actions could be anything, like "middle" "left" could select the next word to the left or go to the beginning of the line.
But my main thinking evolved around game actions, but it is the same principle.
And then you could also advance it with "middle" "left" "middle", the only limit are the coordination skills of your average user.
And ... the hardware limits. I have never really implemented those ideas, because I got frustrated very quickly(some years ago) with how the native touch handling of the OS got in the way, and some unprecise sensor input. But if you keep it simple, it should be doable. I guess I am now motivated to give this experimentation another shot real soon ..
For text editing, I don't think the cardinality of the set of gesture-based solutions is very large.
First, (iOS perspective but it’s not that different than Android) to convert the suggestions row to a row of function keys anytime Shift was held down. No annoying delays or extra taps waiting for the menu pop-up. So now you can use two fingers to cut copy paste undo instead of using several seconds and a popup that can appear anywhere onscreen. Next, arrow keys. Heck, use the same Shift hack and, when Shifted, replace the space bar and the dead useless area below it with a big inverted T. Our phones have gotten much bigger and yet especially on iOS the keyboard hasn’t grown a pixel since what, iOS 5? Case in point: no number row still for Apple, even as an option. Wtf.
2 fingers is already too much. Maybe I could've done it with 2010 smartphones, but new ones are so large that I switched to double-tap then drag ages ago. It's annoying having to involve a second hand just to zoom something, and trying to do it with a single hand is just a recipe for destroying your phone.