I'd mostly like to see a revised edition be clarifications and Effects/rules tweaks (like the Condition adjustments mentioned) that don't actually change any of the core systems. That way all of the 3e material is perfectly useable without any conversion.
I definitely don't want to have to buy something like "Freedom City 3e revised edition."
If I were to revise the Freedom City setting, I'd establish a break between “the past” (definitely covering Freedom City's Golden Age, with exact years given for everything) and “the present” (including “the recent past”, with dates given relative to today; e.g., “ten years ago”, “last year”, etc.). The reason is that Freedom City has kids in it; and kids have a nasty tendency to grow up faster than you'd expect if you don't “float the present”.
As such, the first edition of Freedom City is already hopelessly out of date because roughly a decade has gone by since it was published: the guys who were teens back then (both the “Hero High” crew and the kids of the FF expies) should now be graduated from college.
A floating “modern age” would allow the Freedom City setting to remain current a lot longer; if you go by the examples set in DC and Marvel Comics, decades can pass in real-time with only a year or two passing in the setting (in terms of how old everyone is; the actual year and the surrounding culture and technology still evolve normally).
But in terms of Hero's Handbook? I don't want a 4e. Mastermind's Manual, yes; Mecha & Manga, perhaps (though the really good stuff from there could go into a new edition of Masterminds Manual; I'm looking at the “Conflict and Challenges” section that lets you put social conflicts, performances, and/or dream/soulscapes front and center alongside or instead of fighting). I'd even go with a revised 3e (I'd love to see some tweaks to the Abilities, with “anything ___-related that isn't covered by skills” fleshed out; Stamina, in particular, doesn't seem to have anything to do by itself; everything it does is covered by Fortitude and Toughness). But not a 4e.
Another minor revision I'd make would be to the Effect types: it's a minor thing (which is why it would be suitable for a revision), but I've found that I can mostly replace the “General” type with an “Alteration” type: Elongation, Enhanced Trait, Extra Limbs, Growth, Insubstantial, Morph, and Shrinking can all be thought of as powers that alter the hero in some way. That leaves Feature, Healing, Quickness, and Variable: I tend to think of Quickness as a Movement effect, though I could see calling it a fringe case of Alteration (kind of like Enhanced Trait); Healing is a kind of “anti-Attack” in that it works like an Attack that removes damage instead of inflicting it; and Feature and Variable would both have a “varying” Type, depending on what you do with them.
I could also see combining Growth and Shrinking into a single “Size Control” effect, where you split your ranks between those that let you increase your size and those that let you reduce it; and possibly remove Healing as a distinct power and instead give various Attack powers an Extra that inverts their effects: Affliction cures, Damage heals, Nullify empowers, and Weaken reinforces.
Uh, Freedom City 3e just came out. We aren't revising it anytime soon.
ALL HAIL THE SPAM-O-MATIC!