[4E] Imposter's Armour

[Razmath]

So, recently I've been genning a Doppelganger Warlock for an upcoming adventure I plan on running. While I was looking through the Adventurer's Vault for some fancy magic items I saw the Imposter's Armour, armour that gives you an at will power to change it into whatever normal clothes you want, this seems like the perfect thing to give to a Doppelganger. Unfortunately the only armours this can be used on are Chainmail, Scale and Plate, I can't see any reason not to extend this to all the armour types though.

What do you guys think? Would this be reasonable? If there's another item with a similar effect I probably won't bother, but otherwise this seems like that way to go.

[Townopolis]

The hat of disguise still exists in the world, although at low levels it would definitely be cheaper to get the armor. It also overlaps with your racial (the hat).

The thinking behind making it heavy armor only might be to prevent rogues from nabbing the stuff and just using it in place of normal roguish activity. Still, it can't be any worse in that regard than breaching armor.

I see no problem with letting your character have a set of imposter's armor. I might, however, rule that it only works for your character (in case the rogue wants to borrow it).

[Razmath]

The Hat of Disguise looks pretty useful actually, I kinda prefer the armour though, seeing as it's a polymorph effect rather than an illusion. Also, I don't much like having overlapping abilities, it seems a bit wasteful to me. Still, thanks for your input.

[Burley]

It is wasteful to have overlapping abilities, especially in 4e. With all the circumstantial bonuses, you want don't want to waste a static one that helps you out.
On the matter of the armor: I usually feel that armor prerequisites are lame when going down. I wouldn't allow cloth/leather enhancements onto plate, but I think if something works on heavy armor, it could work on light armor.

The reason why it's made for heavy armors only is because when it's in clothing form, the penalties are gone (as well as the armor bonus). If you're making light armor with the same rules, you lose the AC bonus and get nothing in return, except for different clothes.

So, since you're getting no mechanical benefit (you're actually taking a mechaincal penalty) I'd say it's okay. I'd allow this one into my game.