So they expect everyone to arrive before 7AM, queue up, and then sign up for a time slot? No way I'm driving from the west side all the way to Kokohead at the buttcrack of dawn and then potentially have to come back hours later for my assigned time.
This isn't a bug in their strategy plan, its a feature. 
I think you can sign up anytime after 7. If you arrive after 10, and the next opening is at 1:00, you can leave and return in time to make the 1:00 slot.
I think this is an improvement over the old system. Before, if you showed up at 10 and there's a waiting list, you put you name on it when you arrive and hang around until it's your turn.
If the wait is relatively long, you could be at the range for an hour or 2 -- or more -- waiting for a spot to open up. With the new system, you're signed up for a specific time and can leave and return if it's a long wait.
That's how i see it, anyway. Nobody says you have to show up at 7am. But, if all the slots that day are already taken before you get there at 10, you're out of luck.
Limiting how much time each reservation can take is also a good thing because the days are cut to only Sat & Sun. That's going to create much more weekend demand.