I’ve talked about house rules before and why some are worse than they seem: double-rolling hit dice, realistic sneak attack and 3.0 power attack are some examples. Today’s crap house rule is weapon fumbles on natural 1.
Dropping your weapon on an attack roll of natural 1 is so common a house rule that many players assume it to be official. Rules as written, a roll of 1 is simply a miss. Some DMs like the added risk of a fumble, but there are a number of reasons why it might not be a good idea.
First, it adds in a greater element of random chance, which usually favours the opponents. Your opponents are often weaker, and more numerous, so one of them dropping a weapon is less significant. They are also more likely than you to use natural weapons (bite, claw, etc), which cannot be fumbled.
Second, it’s annoying. In third edition D&D, you waste the rest of your full attack and have to spend a move action to pick it back up, which provokes an attack of opportunity. In fourth it’s a minor action to recover the weapon so you only really lose one attack, but it’s still annoying. In addition, unattended weapons are vulnerable to being taken or damaged.
Third, it strains believability. It makes sense that a legendary warrior might still fail to make the occasional attack, but not that he drops his sword at least once in every battle. You can soften it with something like a Reflex save, but fighters have the lowest Reflex, and if you feel the need to soften fumbles there’s a good chance you don’t really want to use them.