Ummm, I hate to say this, but giving another skill to EMT's because medic's need more practice? I hardly think that is the case. The King Airway is a rescue device for medics with ET intubation still the gold standard. But there are some patients, no matter how hard you try, without some assistance from other toys that are an option within the ER/OR you are not going to get them intubated. I'm sorry, but that's just the case. If I'm picking my back up airway devices, I want a King - not an LMA (to easily unseated and if they start waking up, the potential for aspiration is great), and not a combitube (too much potential for airway trauma creating an even more difficult intubation). Also the king is much easier to intubate around than the combitube. As others have said, the bougie is a great thing - try it and see (and yes preloading it is not that unusual AK )Especially in cases like this - drop your bougie with King in place and you've most likely got your tube.
As for medics not having adequate intubations there is no reason for it except pure laziness on the parts of the departments. It seems when in class, it's all important to make sure your skill sets are good, but I know medics which have gone several years without getting one simply because they haven't been on that few lucky runs that required an intubation (I am aware of one that has worked 5 years and aside from his refresher which is every 2 years and requires one successful intubation on a mannequin he has not intubated). Demand of your training officer, (if that doesn't work start going up the chain all the way to the med director) that you need to adequately maintain your skills. Trust me, when you remind the med director that you're working under his license, he will find a way for you to get intubations because if you screw up it falls back on him, and no doctor wants that. Med directors sometimes forget that, so when you remind them of that they find a way to help you get what you need (if they won't perhaps you need to look for a new med director).
As far as adding them/taking away from basic skill set. It's more simplistic than a combitube, and that is within the majority of BLS service's skill set so why not exchange one for the other? It's meant to be a temporary airway, not long term (less than 24 hours) and will most likely be exchanged for an ET at hospital or when ALS arrives. Let's think about what is best for the patient until ALS arrives or gets to the hospital, and if the King is an adequate airway adjunct or rescue airway I think it will work.