I'm A Banana
Potassium-Rich
Then you're back to the implication that without putting that template into motion the DM is "doing it wrong". I mean, there can definitely be some phrasing that makes it clear, and I don't object too strongly to that, but you've got to be careful with wording there.
I really don't understand where that vibe could come from. It's pretty evident that encounter design is in the hands of the DM, this is just one suggestion, a tendancy, a "default," maybe, for encounters with the phane.
I mean, he's going to have a smaller attack bonus, lower defenses, and less HP anyway, right? Are the PCs going to be counting it all to make sure you applied the template correctly? Shorthanding this kind of thing is better.
Maybe yes, maybe no, but that's an entirely different debate. WotC isn't, by all appareances, even giving us the option of having that debate, since the phane has no noted ability, propensity, desire, or proclivity to make or interest in making time duplicates. That little bit of evocative interest is sucked right out.
So arguing about how it should be done is fairly pointless -- the phane thus far has told us that it won't be done, period. Which robs some of the evocative interest out of the 4e phane that the 3e phane had.
I wouldn't mind having some suggestions on that, but be wary of the possibility of sending the "you aren't really using this monster right" vibe.
I'm not sure it's ever really possible to use a monster wrong, as long as the players enjoy beating the crud out of it and accomplishing whatever goal that lets them accomplish.
Time duplicates, stolen time, and death by rapid old-ization are all interesting things the 3e phane could do that the 4e phane cannot do, and given that 4e should have no inherent problems with the very principles of 'evil twin', 'stolen time,' and 'death by magically accellerated old age,' it's hard to understand why the phane lost these qualities that made it such an interesting possibility (even if the implementation fell short) in 3e.