With the Mail Attachment Limit now forceably imposed on players, it's long overdue that you guys in the Dev Team, create somekind of DOFF Storage system that does not impose on players.
Like a Starbase Holding Area (tank), where people wouldn't need to stuff their DOFFs in the Mail Attachments, bogging down the mailing server.
Because most players are already at their 400 DOFF limit and they aren't going to waste Thousands of Zen to buy more Character slots with 400 DOFF slots, no sir. Gaurantee they will take advantage of the Free Accounts and create Storage BOTs.
So Dev Team, ball's now in your court. Else you are going to see plenty of dissatisified customers leaving because they can't have fun to earn Fleet Marks, or their Starbase progress stagnates.