Prestidigitation! for all your "the dm is enforcing boring minor activities as not being an automatic part of downtime" woes.
Simply put - the game is supposed to be fun. "Hah, you take a -2 on your attacks because your bow is still strung!" is not fun. If you think it is, go compete in the accounting olympics or something and leave honest, hard working players alone.
Ok, take Prestidigitation, it will only take longer, cast spell, then string bow, stringing a bow still takes same amount about of time now added to the time to cast a spell.
Have you never seen a movie where a gun slinger runs out of bullets? or drops his gun? It may not be fun for the gun slinger that he now has to find more bullets or scramble for a new gun, but I think it definitly adds a sense of realism and "scare". Like... "Oh S#it, I just broke my bow string and 20 orcs are coming at me!" RUN!
As compared to "oh, you mean only 20 orcs are coming, I use my "shoot everything in sight" and kill them all. Give me my exp, and next encounter.
It sounds like you like the more, you enter the dragons lair and he's dead, died of old age, since you're the first to find him, you get 100,000exp for the encounter and can take your time looting through the piles and piles of treasure. Next cave you find...
I want to make players feel they earned what they get. Otherwise why not start out as gods?
Right now we are using a full round to string a bow, assuming you have string ready.