one thing that wouldnt be too bad would be an option to either
a) remotely kick any activations of PCs that e.g. dont work anymore
and/or
b) allow the user to set a timeframe after which the software would need internet access again to re-enable the activation, while a slot that has expired will become freed again.
a firewall is for the internet anyway, so it isnt too much of a thing and it would be an optional idea anyway (at least for GW1 users).
for subscribers the GW would need internet anyway after the sub expires and it would need to check whether it was renewed or not, and that could be used to free up licenses of possibly dead installations.