A recent post in the City of Heroes/Villains forums provide a hint on some things that are coming in Issue 16, with Issue 15 soon to be released now.
Issue 16 will not be the issue when the new expansion will be released and the post just shows two pictures. But given the names of those pictures they do hint at a new customisation feature – colour change of pets and powers. The pictures show a fire controller and a fire dominator, but with new colours for their pets and their firepower.
That is a pretty neat thing, even though it might not be something to scream and shout much about too much outside the core fanbase.
More information will be coming for Issue 16 in July, which my guess is means that it might be released some time in September.