No one's suggesting that Froome has abused the system in this particular instance. (Well, I expect they are in the Clinic, but hey ...) These latest relevations are, in themselves, a bit of a damp squib. Froome's just one of the famous names in this un-exciting leak.
The real issue with TUEs is highlighted by US runner Lauren Fleshman's reports of getting asthma medication on TUE and being pressed by Alberto Salazar to use the medication in a manner at odds with the medical advice.
@coffeejo bandages & plasters aren't on the WADA banned list. Painkillers are an interesting one. There was a bit of a fuss about Tramadol abuse in cycling recently but I can't remember what came of it. I don't think it's been put on the banned list since.
I certainly don't trust athletes in general not to abuse any and every potential loophole that appears, and TUEs do present a tempting loophole.