Top leadership should be transferable if people can't play due to RL issues. Maybe after 30 days not logging in, another SG member can take the leadership and transfer it to whoever. And this not necessarily the SG Creator -- they might be the one not logging in! Autoboot options for players not logging in after set periods of time should be available, also an option not to have any autoboot..
The costume for the team should be a choice of changing the color, or the form, or both. Logos should be optional, and there should be a chest-pocket logo option. The costume should be alterable at a later date (as to color or form or both) by the appropriate leader in the group. Maybe this costs influence from the supergroup "bank account"? If there are costume options that aren't available across all body types (e.g. hair styles), then they would not be part of the group costume chosen. Or those options would be able to be set by each individual player.
If you don't want to raise the 75 member limit, please allow alliances so we can easily chat among the minigroups that we play in. I'm for a higher SG maximum number, but really I just want to be able to find the people across the various teams I play in.
5 ranks would be a nice expansion.
A switch to view only the SG members who are on, or all the members online or not (as currently). This makes it easier to manage long lists for big SGs.
Paragonian citizens chat about SG accomplishments. Heroes can look up SGs at the info terminals. The SG can write a short history/description to display in the terminal. ...
Lots of good ideas and implementations in this thread. Haven't read them all.
