So, another thing that I never thought would happen... happened: I completed the last boon from the Well of Dragons campaign. Once I realised how easy Linu's Favor was to gain through doing Temple of Tiamat, it was only a matter of time. I wasn't joking when I said I only needed to do it fifteen more times: That's exactly what I did, one day at a time.
Mind you, most of my runs weren't quite as fast and smooth as that first one, with most of them needing two or three "head phases" to get Tiamat down. One time it even took a full five rounds; I was very surprised that we didn't hit some sort of enrage or fail state considering for how long that fight had been dragging on by that point.
It also took me an embarrassing number of deaths to I figure out how the dragon souls and the five heads' various breath weapons work. On top of that, it wasn't until I did these runs that I realised that the hoard in the Well of Dragons actually has a purpose in the form of buffing the combatants and increasing your chances of good loot! I'd always thought that it was just some leftover from the old days required to originally "unlock" the Temple of Tiamat.
I could see myself doing this on some of my alts now... though not immediately; two weeks of slaying a giant five-headed dragon every day are quite enough for now.