Here my suggestions:

1.- Colors to the homebases such the cities.
2.- Resize armies in homebases of allies.
3.- Attacks Shield free to noobs (until 1 week) then disappear it.
4.- Nuke shields free to noobs (until 1 month) then disappear it.
5.- Shields caducity (to Cities and homebases).
6.- Game Over for who has zero armies inside his homebase
7.- Allow allies inside homebases.

Here my reasons:

1.- Fast detection when someone will attack you or some allie city.
2.- Will help new alliances moving armies till reach any target (homebase or city).
3.- Protection to newbies who begins to know the game, they have one week to know it while collecting resources, after the one week, they will buy protection to their homebases (Will help new alliances).
4.- Of course! My vote for nuke homebases.
5.- My wish since before the last reset.
6.- The One Million USD Suggestion!... In this point the users are obliged to keep activity having to take care of their homebases for not to be expelled of the game (Mickey: Paying to reentry?)
7.- For protecion and to keep one army inside to survive in the game.