It could rely heavily on classic terrain and general mechanics to lessen required dev time. It would have very similar feel and style to Classic. Reverse zones like the Plaguelands to pre-WC3 lore, to look more like Hillbrad, etc. Maybe level cap of 30 for first patch, with potential for increase, perhaps with final “expansion” being Classic which would change the terrain to Classic and increase level cap to 60.
Mageweave could be the highest cloth or something, all of those items etc. are already in place.