Sounds good what you're saying. You're the expert, but guess your idea makes very good sense.
Every case is different, so for as long as flexibility remains, like e.g. adding order statuses (or maybe even removing/skipping/unpublishing one or more from the core), it should be good. See, not every Market is like an Etsy. My case, where I need more steps and keep vendors and customers separate until late in the order process, might be extreme, but think brokerage where you simply don't want customer and vendor to know each other or even communicate before a "secure" stage is reached in the transaction. Well, I'm sure you know.
I was looking at order status ACL as a workaround, fearing it to backfire somewhere on the Shop side, e.g. order statuses become useless or even blocked on the Shop side and the system coming to a screeching halt, eventually. While it might still a valid tool, let's keep an eye on possible side effects...
Next thing, maybe some "if" in PHP. I'm not good with that, but might need to try (or cry for help) if no other way.
Also found a way to hide orders with certain statuses per CSS, but you and I are not the only ones having a driver's license for Firebug or similar, so it's too unsafe, making it a no-no.
After all, your "official" solution looks best, and will be best, I'm sure. Usual question: when? Maybe I won't need an "if" condition, or long testing all across the site after applying ACL. Let me know if you need a guinea pig. Nope, not on a live site.
Thanks & cheers!