What changes can we expect from the maint?
It was an unscheduled maintenance meaning it wasn’t a planned one. This usually occurs if there is a hardware problem rather than a software. A software would require planning and usually is planned fixes (aka patches). Server maintenance for Anet is one that they can usually perform while the game is running (as shown by the months that the servers have been up without disruptions). They are using the same tactics as they used in GW1.
So based on the evidence present it is most likely something physical happened which caused a physical issue that had to be dealt with immediately. This is speculation based on how fast they reacted and that it was not a planned event.
Based on this there should not be performance increases, graphical bugs (unless hardware caused more damage then expected), UI bugs, or TP bugs.
[GWAM] and [LUST]
Mess with the best, die like the rest.
Maybe they added a couple more sticks of RAM ?
I’ll guess they had problems with their storage arrays. Enough drives going offline in a RAID cluster and it’s better to shut down, swap and rebuild the array without a constant stream of pokes from users.
If they detected something as bad as a breach they would have simply pulled the plug (you can’t hack what’s not online) so it was more likely something teetering like an array failing that they could give us a heads up about it a few hours before they shut it down.
RIP City of Heroes