those sound like critical fumbles, ie. something bad happens when you miss, beyond not hurting the bad guy
I'm not a fan of critical fumbles, as a player, it sucks when they happen to you. For a monster, that only sees play for 6 rounds an enemy, they don't happen that often. For a player, which sees tons of rounds of combat, they will happen a lot, and they pile up to kill a PC. Assuming 13 encounters per level, at 6 rounds of combat per encounter, that's 13*6=78 rounds. Using a 1 for a fumble, that's 1 in 20, I will fumble 4 times per level, possibly fatally (depending on the tables used). If you never miss, you never fumble. If you never attack (wimpy wizards perhaps), you never fumble.
As a martial artist, I've never hit myself with a sword. I've never cut myself with an axe while splitting wood (and I've cut my share of wood). katana wielding folks have cut themselves drawing/sheathing their sword (newbies, usually), but even that's rare, and it's not fatal. Falling down in a fight does happen, but it has nothing to do with whether you hit somebody (you can trip during a hit, taking a hit, after a hit, etc).
Overall, I've found most folks critical fumble tables to be far too lethal, and tied to the wrong things in combat.
One thing I did like, was Critical Events from 2E's Combat & Tactics book. It was a table of "stuff that happened" during the round of fighting. It was a 1d20 table, that happened in 1 in 10 rounds. Things like, fights shifts over a few squares (forcing 5 foot steps in 3e terms), furniture broken, one combatant tripping, etc. These events weren't tied to attack or damage roles, because these events happen in a fight, regardless of if you're attacking, defending, hitting or missing.
Lastly, since D&D hit points represents a lot of things that keep you from being dead, not just obvious wounds, there's no specific hit locations, or injuries, so it gets more complicated modeling that stuff, by tacking on special combat effects.
I recommend checking out critical events, that I refer to above. They can add some spice to combat.
