I think OP has the right approach. Although as others have said, just skip the academy in that case, and have each Z do a mini-academy with the relevant airspace/procedures.
Honestly though, enroute would be totally 100% solvable by direct hiring. There's no reason there should be hopping around from one Z to another. An enroute facility is basically set up to be a newbie to retirement one-stop shop. When my brother was applying to USCIS, he applied to two field office openings in locations he was interested in, which was in IL and Wisconsin. Because USCIS does direct hiring, if he wants to ever transfer, he basically applies again to another opening along with hundreds of other people.
Right now we have stuff like:
- Someone from the PNW picks ZAU as the least undesirable option. In the next class, someone from Chicago has ZSE as one of their options. So you will need to train 2 controllers at two different facilities rather than four controllers at a single facility if a swap were theoretically possible. So much wasted training time and $$. And it's not guaranteed the Seattle guy will eventually end up at ZSE and the Chicagoan will make it back to ZAU (just picking two random facilities here).
- Someone picks a highly-desirable fat-staffed Z (e.g. ZHU) because they'll have the highest probability of GTFO'ing to their dream location, whereas half the class would've taken ZHU and stayed their for life. Again, you need to train two controllers twice over at a minimum rather than more controllers to boost staffing.
- People picking prison locations praying for miracles which 99.9% of the time won't happen: ZOA and ZNY in particular. Sunk cost fallacy is a real thing and you end up with miserable controllers, people quitting after a lot of time and money has been invested in them.
Direct hiring would eliminate and/or strongly disincentivize most of these problems.
With direct hire, the marketing/recruitment should also be left to the useless management at each facility and part of their performance evaluation should include how well they are doing staffing the facility. Someone at a community college in Oakland that sees a poster "Become an FAA air traffic controller" probably doesn't give a sh*t. Now replace that with "Make $200k+ down the road at ZOA with your otherwise useless 2-year degree" and suddenly you'll see interest perk up. They should be sending out reps to every drive-thru, job fair, community college, high school spamming ZOA.