But there's no way to keep those abilities and still keep to the 4e philosophy on monster design and balance.
Ha!
I mean alternate cowboy dimension duplicates require you to have stated out versions of the PCs or alternate versions of them at least.
"Your evil twin attacks you. Eddie, roll to attack yourself at -2."
As a DM, I should have a vague idea of what powers my PC's have anyway, and even if I don't remember specifics, it's right there on their character sheet, and THEY have the specifics, so it's no more effort than telling them what the twin does, and letting them figure out what numbers to figure in. It's less DM prep work than most other monsters.
That means you need access to their character sheets in order to apply a template or modifications to them. They might take those home with them. Either that or it requires you ask the players what their AC or attacks or damage is each round of combat. Plus...that PC has 20 different powers you could use, each of which has a paragraph of text describing it. How do they all work? Which is the best one to use this round? How many of them are Immediate actions? It's easy for the player to keep track of all that, he isn't running 3 or 4 other creatures at the same time.
You don't need to keep track of it. The player has it done for you. You can also take a glance at their character sheet before or during play, and if you remember a particular ability, you can declare that they use it against themselves (or whatever). Really, you're assuming it's harder than it is (speaking as someone who has run evil cowboy dimension twins against PC parties in the past, they required the LEAST set-up of any monster I've ever run).
Plus, you run into a problem with action economy. By summoning an external creature, the monster now gets 2 standard actions a round and can essentially attack twice. Does it take the standard action of the time creature in order to keep the duplicate going in order to balance that? It just isn't a feasible power. Also, if it is summoning creatures what is the purpose of the time creature? What role does it serve? Is it a striker since it is creating creatures to do damage?
And now you're careening off the edge.
First of all, we have an example of a monster who summons other monsters, so action economy can be accounted for.
Second of all, the initial idea was to not have it summoned during combat, but appearing as part of the encounter, thus being like any other normal monster or minion, rather than just piling onto the phane.
Nothing in 4e prevents evil cowboy universe duplicates attacking the PC's, because I'm sure the designers wouldn't be so cavalier as to eliminate that classic trope from the game.
So the only question is: why did the Phane loose this ability?
