I'll give that a bit more thought. Conceptually, it's a little harder for me to make rigs fit in with CR recovery, helping with external weapon loading aside. (Yes, yes, I know, the "realism" argument isn't a good argument.)
A mobile gantry could be just as useful for maintenance as it is for emergency repairs. I imagine it's a heck of a lot easier to pull off all those hull plates covering the engines when you have a stable external scaffolding to anchor yourself, rather than having your crew floating around out there in EVA suits, and once you have the hull plates off, it'd be pretty handy to have a massive crane there to pull the engines out to where you can change that worn out plasma regulator, instead of wedging yourself into tiny crawlspaces.
For a present day analogy, it may be possible to change your car's oil with nothing more than a bucket, a tire jack, $10 worth of wrenches, and a lot of swearing, but putting the car up on a proper lift makes the job far faster and less tiring. (Don't get me started on the time I fixed a leaking cooling system on the side of the road with a literal aluminum Pepsi can.)
