This.
By disabling digging you're taking complexity out of the game, dumbing it down even more, a thing that I believe many of us are a little disappointed with. At the same time I agree with Vedui, it really doesn't concern anyone how he plays, except him while he's playing his SP game. TFP trying to "police" every single aspect of the game because "the only safe place is the Title screen" is just not an efficient use of their time.
Many of the people I have read posting here, make their "day to day living/crafting base" underground. They still have a horde base in the surface to enjoy horde night (I enjoy it, makes all the hard work of finding better gun part... errr... looting feel worth it)
If it comes as an option, good! But to be honest the only thing they had to change is the ridiculous supersonic hearing of zombies. I for one hate digging zombies because one of my most loved activities in this game was mining. Had a mine in each of the biomes for ammunition. (and they were BIG mines too!). It took the edge off the game for a night or 2, while feeling I wasn't wasting my time as I was gathering resources for my projects. Kind of impossible now, even with perks.
As mentioned in other posts; an Oxygen system, Worms, or some other kind of threat for underground would be nice. NOT supersonic hearing zombies from above 40m layers of stone.
During horde night, EVERYONE should be ♥♥♥♥ed if underground. That's the point, they can SEE you.
(Unless you planned and invented some base design that can deal with horde night underground)
TL;DR:
Option to dig: good
Fix zombie hearing/detecting you through 40m of stone
On horde night, all bets are off. The can SEE you. Get ready.
Stop caring one ♥♥♥♥ of how other people play the game... EXCEPT in MP. (That will be a female dog to balance and I'm not touching that one)