Encryption adds ~5% to CPU usage (this means if CPU usage was 1% it will became 1.05%, not 6%) on both client and server side. Encryption adds NOTHING to network bandwidth.
Encryption can't be turned off by security reasons. We fully understood that someone may like to have 5% less CPU usage on client or server computer, but we also cares of corporate users. If ability to disable encryption is given, corporate users will surely use it, and after they are sucesfully 'hacked' they will claim that this is becouse our software is unsecure. So encryption can't be disabled for good.
Same goes for password. Again, we fully understood that it's very boring to enter password every time you want to connect. But if we allow to save password, users will surely save them on public accessed computer, in internet cafes etc. And, again, after 'hack' all claims will be to us that 'our software is unsecure'.
Radmin is positioned as secure corporate solution, so we just can't afford to enable options like 'remember password so anyone can access remote computer' and 'turn encryption off so anyone on my network can monitor my actions'.