All your feedback has been noted.
Just to consolidate my thoughts on this.
1) The target audience on these really needs to be selected. Are they intended for players who understand the dungeons or are they intended for players who have never seen them. If the former then discussions of boss abilities is kinda silly, if the latter why are you showing CMs at all? CMs pretty much require knowledge to enjoy watching they aren't something the uninitiated can watch and get anything out of no matter how good the spectator view and commentator quality is.
2) Commentators need to be more familiar not only with challenge modes in theory but in practice. So many times comments were made about trash skipping mechanics but anyone who has done the CMs knows that both groups were following pretty standard pull patterns. A commentator who was more familiar with the format in practice could talk about how they are taking difficult packs specifically rather then offering basic boilerplate about how they are using stuns and aoeing. Even comments on comp balance and the implications of the comps used on strategies was missing.
3) Spectator UI. To watch these intelligently I'd like to see raid frames and the objectives UI with timer and mob counter at the minimum. Ideally the UI should just be one of the players that way we'd have a lot of info. Also drop the big frame, make full use of the screen.
4) The format needs to be worked out. The format used at the launch event would be pretty good, give each team a finite number of resets to use, either per dungeon or over the entire set and sum times. This would also let teams pull as aggressively as they might want in a full speed run so the times they put up would actually be good times. Related to (3) I think it would be better for the teams to run one at a time, it would take longer but trying to comment on two groups simultaneously makes things more confusing then need be.
I'm still skeptical that CMs will be all that interesting to watch for most players in general since the subtlety of paths taken and how certain pulls are approached will be lost on them. However if the goal is to make CMs work the 4 things above would make them at least a lot more fun for people who do understand whats going on to watch.