JP doesn't have that much space for a well themed low to ground "thrill" Coaster. However, a family coaster could work, and is definitely needed.
And for those thinking about "thrill with minimal theme" Coasters like rockit, hulk, and dragons are still on the table for universal, think again. Rock it was only added as a filler to somewhat increase park attendance during the recession, and Hulk and dragons were added back when uni thought it was a good idea and to separate themselves from the mouse.
P.S. I don't think we will ever see a B&M again at Universal, after the disappointment of the hulk upgrade.