Variant Rules from the DMG, for Combat in My Campaigns

[Plane Sailing]

You must roll a check to avoid a fumble. A fumble check is a d20 roll plus the same attack bonus you would've applied to the previous roll, if you had not rolled a natural 1. The DC for a fumble check is simply the AC of the target of that failed attack roll.

The problem with this is that you are more likely to fumble when attacking someone stumbling aroudn in plate armour than when attacking the finesse fighter who is dancing around.

This doesn't make sense. We used to use it in our game, but eventually switched to a straight DC15 Reflex save, and that has done us admirably for the last couple of years.

Cheers

 

[Tilla the Hun (work)]

1. INITIATIVE: ROLL EACH ROUND

Well, not "each round"...

I think rolling initiative at the beginning of each round (and then gathering and re-recording those initiatives on whatever you use to keep track of each PC, NPC, and creature in combat) is too much, as it slows down combat considerably. However, I also think it's not enough, rolling once for initiative at the beginning of each encounter.

So, my compromise is to use "median" rolls for initiative. What this means is, you roll three d20 at the beginning of each encounter; you discard the highest and the lowest of the three rolls, and you apply your initiative bonus to the remaining roll. That determines your initiative for the entire encounter.

It's an interesting idea. Here's a slight variation that a) removes randomness entirely, and b) rewards Imp Init -always-

Just use the initiative modifier of the character as an initiative. If two players are on the same initiative, let the players choose who goes first (Lars looks to the wizard to see if he's casting a spell) and keep that order. If it's players vs monsters, use dex scores or let the players go first.

I've not used this idea yet, but it strikes me as streamlining combat to no degree - I always know whose going first in combat They players and opponents can mix up the order via using special actions, but in the first rnd, I know who to call first.

2. INCREASED CRITICALS

This rules variant makes combat a little more deadly.

The threat ranges of *all* melee and missile attacks is increased by one step.

Example: Using this rules variant, a weapon with a critical of "19-20/x2" becomes "18-20/x2", whereas a weapon with a critical of "x3" becomes "19-20/x3".

Whenever a threat range is "doubled" by something (such as by a weapon with the "keen" enchantment, or by the Improved Criticals feat), it is instead increased by two steps.

Example: Using this rules variant, a rapier has a threat range of 17-20; a "keen" rapier, a threat range of 15-20; and a "keen" rapier used with the Improved Criticals feat, a threat range of 13-20.

While I would agree that expanding threat ranges makes combat more deadly (which some do desire) I must point out some fundamental flaws herein. You mention that you are moving to 3.5. In 3.5, 'keen' and 'imp crit' do not stack, unfortunately (it's one of the things I don't like in 3.5). You can certainly rule 0 that, however.
As for increasing by two steps, I think you might run into some issues when dealing with certain PrC's that increase crit ranges.

3. DEFENSE ROLLS

For simplicity and to reduce the number of rolls, you and your opponents are normally considered to be "taking 10" on your defense rolls, and thus you are using a base 10 for your AC.

However, you can elect to *roll* your defense against a particular attack. You have to declare this before the attack itself is rolled. By rolling your defense, you hope to roll better than a 10 on the d20, thereby improving your AC against that attack. (Of course, you may end up rolling lower than a 10, thereby worsening your AC.)

Note: I'm using this rules variant mostly because I also use "heroic luck" rules that allow players to re-roll the dice, a certain number of times per game session based on a character's Cha and alignment.

Seems terribly overcomplicated to me. I've looked at that optional rule, and while I -like- your modification to 'elect' to roll your base AC, I don't see why some characters would not always choose to roll it. Also, introducing a die roll into AC makes an encounter even more difficult to predict effectivity, impact, and/or to control such an encounter should it get out of hand.
From having looked at this variant myself, I judged it to be one too many die rolls that weren't strictly necessary.

4. FUMBLES

Whenever you roll a natural 1 on an attack roll, you not only automatically miss your target, but there is a chance you will fumble.

To avoid a fumble, you must make a Reflex save, and the DC for this is determined by the weapon you used in the attack, as follows...

Unarmed attacks (including the natural weapons of creatures): DC 15.
Light melee weapons: DC 17.
1-handed melee weapons: DC 19.
2-handed melee weapons: DC 21.
Ranged weapons: DC 19.

If you fail this Reflex save, you fumble, and you must spend a move equivalent action on your next turn recovering. Until you have recovered, you are considered to be stunned, i.e. you lose your Dex bonus to AC (if any), and foes gain a +2 attack bonus against you.

We do fumbles far more simply. You rolled a 1 in combat? Make a dex check, DC 10 (15 if flanked/complications). Fail that, and something disastrous happens (I'll typically roll a d20 behind the screen, high = funny, low = serious, always an abnormal event in combat)

Bottom line: If your players like it, do it. However, a general rule of thumb is "more dice rolling = less enjoyment as combat BOGS down into sheer number crunching". Another is "Less dice rolling = faster combat = chance for MORE combat!"