I very strongly hope it will be as they implied a bit of a treasure hunt like the easter egg mount hunts in Retail (Hivemind, Lucid Nightmare, etc.)
There are people at Blizzard who know how to create good secret hunts, I just hope these folks were tapped for that (and/or the regular Classic devs/designers also have a passion for that)
Obviously they can’t put the same amount of effort into it as these particular easter egg hunts, not if they want to give us 100-600 different runes, but I feel like they should do something like that for at least some of the runes. Various levels of difficulty and all that
I don’t know about Mount reward, not really into that tbh, but title reward for finding them all and the completionist vibe to explore the world can be really fun, challenging and rewarding as well.
Of course i’ll try to avoid spoilers as well! And maybe leave a comment on Wowhead once I’m done to get involved with the community