Now that you made it this far, I think you should consider whether your progress should be champ-based as you seem to be doing, or stat based (acc, resist, etc). Personally, once you upgrade the stat then whenever you get a champ of that affinity you are already good to go. Other alternatives to GH are artifacts which would need to be applied to each champ of that affinity.

I think most would agree that ACC is the most desirable GH stat to have, so I would finish out your ACC upgrades.  This is the subject of many opinions but I would offer that RES is the next most desirable after ACC, then DEF, then CD, then HP, then ATK.

This is a great point. The only change I would say is my upgrade order would be Acc, Res, CD, Def, HP then Attack. :)

Acc, res, hp/def, cd, atk

You can't sway me from Crit Damage. You know the old saying, "The Best HP/Defense is a good Offense" lol

My vote is acc > cdmg > res > hp > def > atk

I can see this as well. In reality, I have upgraded Accuracy then Crit Damage THEN Resist. Although I think Resist is way more important in all the new content than it was when I first ranked up Acc/Crit Dam.

Thank you very much for the advice. Been grinding GH for past few days now to try and save up my medals.

That's (was) exactly my priority.

I went Acc/Crit/Res/finished Force and Spirit HP now and I can't help but feel like Great Hall is the Rorschach test of Raid

Is the reason to do CDam 2nd because of the lack of glyphs?  

Not really. More just that it is almost universally useful, just like acc and res.