It will be a little sad to see some of my favorite absurdities being nerfed, but I can see why (especially the bionics, as much as I love playing a heavily-'meched character). And none of the changes are really crippling, in some cases like the vehicle changes it just pushes the power curve a little further into late/endgame (having to get mechanics 8+ to repair military stuff).
I would definitely love something like a bike rack though. Something that can quickly attach a small (~1x1-3x1) vehicle to a larger one, without having to completely deconstruct and re-construct the smaller vehicle all the time.
I imagine a 1-tile vehicle would be relatively easy to do an attachment for, if you could figure out a way to treat it as a virtual part of sorts, you would just install it to an available tile. Not sure how multi-tile vehicles could be handled, though I guess depending on how the code handles it, it might be possible to make a modular bike of sorts: you’d have 2-3 “1-tile vehicles”, that are actually only functional when attached to each other.
While that would result in not really eliminating the “decon-recon” problem, since you’d still have to take the modules apart and put them back together, it would at least streamline the process for things more complex than a trunksled.
Though, then there’s the problem of how to treat motors on the carried vehicle… if they’re active then either you’d need really high mechanics to mount anything with its own motor or you’d risk allowing “engine-modules” that bypass the skill check on multi-engine vehicles. If they’re not active then the modular bike trick wouldn’t work, and we’d be back to the problem of how to handle more than one tile. I suppose one compromise, though one that would likely be a headache to code, would be to default to installing the engine in an “inactive” state, but with the ability to “activate” it if it wouldn’t exceed the number of active engines your Mechanics skill allows.
Though a side-effect of that would be that while running a huge number of engines simultaneously would still be skill-capped, making super-hybrids that can run on just about anything as long as they only run one engine at a time would become possible at low skill levels. I do not know if people would see that as beneficial or detrimental.
Definitely a hard problem when you consider how it might interact with existing systems.