There is a balance between serviceability and robustness of the build. As illustrated by the fact that one could, in fact, simply epoxy the whole damned thing as long as one accounted for the spring movement of jacks and the space requires for plugs.
But even then, certain devices might suffer from thermal issues. Dunno the R value of epoxy in general.
The most robust way to build a switching system for a pedal would probably be a solid-state FET-based buffered bypass with a high quality momentary switch. Lehele makes one that's supposed to be rated for a million cycles. Also: there are plenty of long-life rated tactile switches out there that you can use with an external, spring-loaded plunger. That takes some engineering work, though.
Thinking about this...honestly, makes a lot of sense why so many old pedals were built this way. Particularly when cheap and robust multi pole stomp switches were less prevalent.
Relays would be a close second to solid state switching. 3PDTs are fragile little buggers if you've ever opened one up. A few bent metal tabs, plastic, and levers. Anything gets fucked up, and the whole mechanism breaks.
The rest...well...
Try to mount your potentiometer knobs with as little space between the enclosure and the bottom of the knob as possible. Somebody steps on one of those, and if there's too much travel it'll push the shaft straight through the bottom of the pot.
Free-wired jacks can be relatively robust, but also remember that if the nut comes loose you might have somebody twisting that son of a bitch for a *long* time before a wire eventually breaks. So loctite is not a bad idea there.
Wire neatly with straight runs onto your targets to avoid excess strain. The idea with electronics grade silicone is a good one.
