I need to be able to hold my finger on a key for pressing on time. I can't imagine how to do this with a "touch"screen. While I generally use a laptop for this, I occasionally use the N900 as a remote (ssh over wlan).
All of my phones have had very erratic latency, even for wifi over LAN. Have yours been consistent enough for this to provide the split-second timing you need?
My N4 is about 3 unobstructed meters from the wifi access point. With 10 samples of each, a laptop at the same distance gets pings to the router ranging from 0.399ms to 0.418ms. The phone's range from 6.89ms to 91.27ms.