When it comes to a replacement, there's really only two types of rides which would fit the IP and provide the thrills befitting for it. A Coaster, or a Slot Car attraction.
If they're intending on keeping an attraction in that building, my gut feeling says it would be a coaster. Since you can certainly shoehorn a coaster in there, it wouldn't be the first nor last time any place has done that. And in all honesty, I wouldn't mind having a coaster with bigger thrills than Mummy...yet isn't so Jekal and Hyde like HRRR.
As for a slot car attraction, that would require a completely different location since that type of ride requires a substantial amount of space, especially if you want any high-speed/racing segment.