I too not against, if code is clear and not unneededly complicated then I would be for inclusion to OXCE.
Only question is how it will be defined in ruleset, how it will handle multiple crafts and how handle crafts that do not have battlesapce mode?
well, obviously, crafts without battlescape data will be ignored. All this feature, IMO, should be locked under ruleset option, as vanilla does not have required date for interceptor and firestorm. Multiple crafts adds a layer of complexity. I personally dislike multiple crafts per hangar, as they even can't be shown in basescape. I know, some mods, like UNEXCOM uses this feature to have tens of crafts in wing formations.
From a game design perspective, if I would like to have many crafts launched in formation from the base I would rather expand the base frame in some way (like infinite base tiles, rejected at some point for both OXC and OXCE). Although, it's an off-topic...
Any way, as I personally don't need to handle many crafts in one hangar, I have to ask - since we display only a single craft image in base view, why we should add complexity to battlescape map? I mean, if the modder will keep new global option false (will be default value, of), they will have current behavior. If they don't care about not having it displayed in base view, why they would care about not shown crafts on battlescape? AFAIK, all mods with many crafts in hangar still use vanilla hangar assets, both basescape and battlescape.
So, I've presented possible solution with rects in message above, but I'd rather gather feedback from the community, if it ever needed. Even if no strong feedback presented, I'd rather make an MVP solution, that would work for 90% cases.