I think the line for Iron Gwazi will be crazy for its entire existence but not just for "popularity" reasons.
My "home" park is Cedar Point in Ohio, which opened a Rocky Mountain Construction coaster like Iron Gwazi, named Steel Vengeance, a number of years ago. While this ride is the best coaster I've ever been on, the "process" to get on the ride severely slows down the load time and increases wait times drastically.
The short of it is Rocky Mountain Construction requires that all riders have nothing in their pockets. No keys, no cell phones, nothing. It doesn't matter if your pockets zip or snap, they must be empty. So, after waiting in line, you go through a metal detector and your hand is stamped with a green or red stamp (green = nothing in your pockets). This stamp tells the ride ops if you have something in your pockets. Then, as you near the loading platform, you have to take everything out of your pockets and hold them in your hand. Once seated on the train, everything must be placed into a zippered pouch under your seat. The ride ops then have to come one-by-one and check the riders' hand (green or red) and verify that their pouch is zipped. Then "shut" the ride restraints.
This load process is then reversed once the train returns to the station. The offloading rider has to wait to be released by the ride op, they then have to unzip the pouch under their seat, remove their belongings, and exit the ride. The time from the point that a train stops in the station, unloads, loads, and is dispatched averages about 5 minutes. No exaggeration.
The sad part is this wasn't always the case, as there used to be no restrictions on pocket contents but there's been some bad apples that have ruined it by holding cell phones during the ride that injured other riders. From what I've been told by ride ops, the empty pockets rule is from the manufacturer directly, Rocky Mountain Construction, and Cedar Point had no say. From what I understand, other RMC rides have the same or similar rules (I know Twisted Timbers does). Given what I've seen with the intensity of Iron Gwazi, I would predict it would too.
I know there are some Universal rides with similar no-pocket-contents rules and from what I understand, they have lockers that are able to be used. So, perhaps Busch Gardens will institute a process like that (nothing in your pockets before you enter the line) but the issue Cedar Point ran into was the installing of lockers was not possible. I've never been to BG, so maybe with will be a moot point.
So, that's just a long-winded answer that I think the ride's popularity (and wait times) will be high for the foreseeable future
