Well, yes - I think a siege coin of Constantine XI would be great for a Byzantine collection, especially for the history (and the fact the silver allegedly came from melted silver vessels from the Church of St Sophia). Most people will never be able to acquire a coin of Constantine XI for their collection of course, but a coin of John VIII will make the same point about the impending end of the empire.
I took a mini-seminar with Prue Morgan Fitts, which was something like a 10 hour class covering only Byzantine and she had dozens of examples in many denominations of all metal types. In fact we still had to go very quickly in my opinion just to cover the nearly 1000 year span of coinage. I like you included imitation coinage. I suppose showing the changing denominations over time would be interesting (and costly). I was always intrigued by the mints that popped up and disappeared as the empire changed size.
i think that's a pretty sweet byzantine survey DS! i made a coin display for my school last summer, and tried to represent the byzantine with only two coins! i picked this one... a nice large folis of justinian the great, and the patina makes it pretty easy to see in the coin display. and a trachy... sorry for this horrible picture. anyway, the coin on the top you can barely see is a byzantine trachy. most of the coins are in a display case, I wanted to leave a few out for people to touch. if someone takes the coins...oh well...it's worth about 2 bucks. i'd be glad someone was actually interested enough to steal one! LOL! below it is a constantius ii LRB. the text above them is the little boxes is a brief description of the coins.
If you covered all the denominations and all the mints, it would be a good size group of coins. Someone mentioned that the US has had few types compared to ancients but perhaps that will change if the US continues issuing coins for 2000 years. First Greek to last Byzantine is, after all, about that long.