Yeah no worries. The guys who will be sent, particularly spec ops, are actually glad of the chance to use their training operationally. If a hostage situation should ever occur on our shores (and its unlikely it would due to our smallish population and superior surveillance), the CT blokes would have a very high chance of a successful outcome because they train like bastards and have first-hand experience of killing people. You can't put a price on that, as cold-blooded as it sounds.
The real threat of protracted engagement comes about if Team 'Murica and Team Straya keep doing what they're doing i.e. announcing everything to the press and public, then putting on staged buildups and coalition meetings before entering the arse-kicking phase.
Once IS operatives get a feel for the vibe, they start infiltrating back into the population, hide their black flags, and turn the propaganda effort into footage of innocents being killed with drones etc. etc.
A couple of military experts (ones I'm inclined to believe) have blamed the US military for the failure of the hostage rescue situations, but announcing they'd fly drones and start S&R for various POI in theatre, who were known hostages. IS wised up to it and moved them on a regular basis, denying Delta or SAS any chance of executing a mission that would not only save Western lives, but dent the current aura of invincibility IS are projecting.
Right now, the CIA and US High Command have every piece of information about the ground conflict they need. The USA has the logistics to get pretty much anything they want into anywhere they want in the world within 24 hours.
This time there is no ground to win; no dictator to overthrow, and no country to pacify. Syria is a fucking basket case the US (and us, by extension) wants none of, and they've already told Iraq to sort their own shit out by withdrawing. But they're not going to stand by and let thousands of people die (and thousands of US combat losses mean nothing) after decades in the area.
This time, the Kurds are fighting them, and creating a conventional conflict on the ground to put up some visible borders.
The operation should be simple: Pick the best and bravest, then get in, absolutely skull-fuck the opposition back to the stone age, and get out again.
Send Iraq the bill.