One thing your improvements do really help is with my Cradlepoint router configuration. It uses javascript to adjust the screen as it reads the configuration information, so the browser previously did a lot of work repainting the entire page for every alteration. It is now much faster (still slow, but not so annoying).

One of the problems with the application manager update parallels this - the apt-worker or something tries to open 16 or more connections (if you've added archives) for updates, and this causes a lot of thrashing, so instead of being faster, it runs several times slower.

The impedance match for a laptop or desktop is different since the CPU and video usually are waiting for the next TCP packet even on a fast link. For a tablet, the CPU won't be the bottleneck, but it will take a while to render any complex page, so doing it too often, especially when only a little more of the page has come down, is counterproductive.

(There are ways of tuning individual applications - my zmapper redraws every road in a 20 square mile area in less than 1/2 a second so can keep up with a 5hz GPS at slightly higher magnifications, but I optimized it like for the old 8 bit embedded processors, and many of the techniques were tuning the update v.s. rendering)