,androidi wrote

WinRT/Metro:

But from the keynotes I did observe that touch+drag operations did appear to have noticeable latency.

Probably because the machines in use were either older machines or prototypes, it was mentioned repeatedly that they're working with device manufacturers to improve any latency issues because they are infintely more problematic when dealing with a touch device than they are with mouse/keyboard combos. I'm also pretty sure there will be lots more works done on this specifically before release.