This seems like a tough call. Keeping out rubble is good IMO, but, yeah, mining doesn't have any drawbacks or dangers. The current overhaul sounds like a great logistical addition, so I agree with not adding even more things to manage in that respect. But what you say, Kohaku, about a structural or environmental challenge would be good. More things to manage, but in a different facet of the mining experience.
Maybe I should work on a suggestion thread, then, to tackle "making rubble a net positive".
Just from curiosity, if we did have rubble that had to be cleared before mining further into a stone face had to take place, but it was capable of being carried away someplace where you didn't have to worry about it anymore (dumped off-map, atom-smashed, landfilled) simply by having a few hauler dwarves dedicated to clearing rubble or simply by extending your cart tracks a few more tiles, would people still be opposed if it took no particular effort on the part of the player to clean it all up?
Or in other words, do the people who oppose rubble oppose having to clean it up, (and hence, would not be opposed if cleaning were almost totally automated,) or oppose it for other reasons?
How many are opposed to just plain anything that slows mining down for any reason, and like the fast burrowing speeds?
If I'm going to be suggesting something that makes as many happy as possible, I'm not entirely sure what it is people are actually after...
I tend to get the impression that some people are actually just unhappy with change in general. They might be OK with adding honeybees that do nothing to change most of the game or bugfixes, but don't want the game to actually become more advanced or complex, and want it to stay "legos with ants that move them around" forever.