I might agree this would be helpful for the many phones plugged into power and on wifi for large portions of the day.  However that doesn't really help much when phone IP addresses change often as you move onto different networks, and currently IP address is the only thing that peers can keep track of for the goodness of a peer as there is no roaming pseudo-identity cookie due to separate goal of anonymity?  I haven't studied the issue if would be even possible to have both privacy protection and unique node identifiers for anti-DoS authentication at the same time.