The only lingering problem could be the cost of running two national tournaments (but I think the cost is well worth the effect of helping more students have more chances at competition and recognition).
It's not just the cost (which is significant). In addition:
-The logistics involved are immense. National tournament committees on average work for about 3 years planning and preparing for the event. it's a major disruption to the college campus, much more that any state tournament. Part of that is because it's really a multi-day event, with activities starting usually on Thursday and going through mid-day Monday. The bulk of the activities of course are on Friday and Saturday.
-Since most teams travel from out of state, there needs to be plenty of hotel rooms and dorms to go around. Hence, it'd be unlikely to be able to run 2 tournaments on back to back days. Rather, you'd have to do them on back to back weeks.
-There is a huge issue with scheduling more than ~60 teams in a day. Right now, we do 10 teams per time block. With ~100 teams, we'd have to do at least 15 per time block. A lot of the specialized labs aren't big enough to hold that many students. And with a lot of the building events, we'd have to have lots of parallel testing stations / courses setup, which will take up a lot more room.