The problem with Bonus Episodes is that they require too much effort/time to fit into the same bracket as an Elusive Target, which I'm sure they can throw together in very little time at all (in comparison). So this doesn't really solve the problem.
What I'm suggesting is that maps/disguises/items were designed in such way that we would no longer need to rely on new maps/disguises/items being released alongside each Elusive Target. I've heard people say it'd be cool if we could dress up as the waiter and lead the target to the kitchen, or maybe offer him a drink. But what if this was something we could to any NPC, on any Mission, Escalation or User-made Contract? Now we have an infrastructure that supports any potential target, regardless of whether or not IO bother to even script him to move from his chair. They wouldn't need to. Their hard work would have already been done.
This kind of interaction is already in the game. We have the officer outfit in Marrakesh which can dismiss other soldiers, and the Masseuse that can offer NPCs a massage. So it's possible, at least on a small scale, but imagine if they expanded this into more disguises.
This is obviously all hypothetical, and it goes without saying that a strict scripted event is mich easier to code than systemic mechanics that players could manipulate in any number of ways. I can only imagine how complex Season 1's levels were to craft as it is. This is just the direction I'd like to see them go in Season 2.