Increasing the mining rate is the only way that they're ever really going to balance crafted pickaxes. I mean there are some recipes we've found that seem to be better value per dura than the vendor ones now, but even knowing those recipes I just find it easier to grab a some from a vendor rather than troubling our weaponsmiths to give me a ton of picks every day I mine.
If crafted picks actually got the work done faster, I definitely would trouble them though.
Easier to do now that the pickaxe and wood axe cost 5s, but even so a full horse load of ore would only cost you 15s in pickaxes which is still negligible.
I just don't see crafting your own worthwhile unless they buffed dura a ridiculous amount, but even then they have to be careful to keep that buff from letting people make silly high dura weapons with gathering tool handle or whatever. Only messing with the head piece would solve that since they have bad dmg stats.
But including some ability to net more ore at a better pace by investing in your tool more is an interesting idea at least.
What's funny/sad is that you could go back 10 years and find people asking for this sort of thing in the old game and we never got anything at all.