7DMT was not testing with humans until right before it opened. They were still testing with weights in April. It also was a new, one of a kind, unique ride system that wasn't even in the original NF plans. It was announced and built in about 2 years.
TRON is a clone. It was agreed that Shanghai would have an exclusive for a few years then the second one (that was built and being stored) could open at Magic Kingdom. They are currently testing humans. That would indicate it is pretty ready ride wise. The delay seems more like an accounting move. Maybe at this point it took so long it can be posted as a loss.