Have you ever used a modern Mac trackpad? They're amazing little devices. I don't want mice anymore.
1. Scroll wheels only let you scroll in discrete steps, which the human visual system is bad at handling. It pales compared to inertial touch scrolling, which actually works exactly like objects in real life, the kind we've been evolving to look at and track for ages. You get instant analog feedback. It also lets you scroll in 2D rather than on one axis. Infinite canvas apps like graphical tools are far easier to use with multitouch than with separate pan and zoom controls.
2. I've found two-finger panning far easier on the wrists than click and drag. Add in three fingered swipes (i.e. switching between virtual desktops horizontally, zooming out your windows vertically) and it's ridiculously easy to get around. On Windows, task switching was always a pain. On a Mac, I have a dozen windows open easily at any given time.
3. Flinging over and over is not a big deal because a) there is non-linear acceleration on the gestures and b) after flinging twice, the third fling will have vastly increased speed. It is much faster than waiting for that middle click thing. The middle click thing is also limited by where you click. If the window is near the edge, you can't go as fast.
Finally, multitouch gestures can be combined, and Apple has done an amazing job in the drivers for this. I can click on a file with my thumb to start dragging it, and then while holding it, do a two finger scroll or a three finger flick to another desktop or window at the same time. It works so well, you just do it naturally and only realize later how damn clever the code is to be able to disambiguate your touches.
I tried using a "multi touch" Samsung laptop too. It was a complete piece of crap, which would constantly detect phantom gestures, and was entirely context independent. For example, it would trigger rotation in apps where it made no sense at all (e.g. the browser), and the trackpad surface was so sticky my finger skipped over it constantly.
Don't knock multitouch until you've tried an actually good implementation, with software designed to make it shine.