5th Edition Rolls With 2d10 Instead

    I did a post a while ago looking at the DCs and odds of success for the 5e SRD.  I made the mistake of telling a friend about it.  He said, "well, you like the idea of rolling 2d10 instead of 1d20, so how would that change the odds?"  I hate him.  Don't get me wrong, he's my best friend and the coolest guy I know and nicer and more patient than any human has a right to be.  Still, I hate him.  He tends to say things like this that send me into some new project black hole that I may spend the rest of my life on.  In this case it isn't so bad - but making the table for all the odds in 5e was a lot of work, more work that it looks like, and making this damn table was a lot of work too.  Still, he was right, so let's look at what happens if you roll 2d10 instead of 1d20 with 5th Edition :)

    First off, why roll 2d10 instead of 1d20?  Well, multiple dice create a bell curve.  A single die is flat, it has the exact same odds of rolling any number, like so (again all this will be thanks to AnyDice.com)...

But add in a die and you create a bell curve, now the middle results are more common than the extremes...

The reason I like this idea (though granted I have not found a table to try it) is from my experiences with Pathfinder combat.  I'll give you the biggest example that comes to mind.  Some time ago I was working on an adventure and decided that I wanted to throw in a special encounter.  The evil Drow, dark elves, had been messing around in the background of the world and I wanted to have the party encounter them for the first time.  So I set up an adventure that would culminate in the party facing a group of Drow.  They would talk at first, the leader challenging the party's main fighter to a duel.  Everybody else would just watch the two champions face off.  But they wouldn't, after the 3rd round the Drow minions would ambush the party - showing how they were evil sneaky bast**ds.  Also I was going to use a new system where the Drow mages couldn't cast spells but could spend their slots for instant counterspells and to re-target the party's spellcaster - though that's tangential to my point, sorry.  Anyways, I crafted this Drow champion by hand to make sure she would be a good threat to the party's main fighter so we'd have a cool fight scene.  I didn't really narrate it as well as I should have, but the thing that killed the idea of this dramatic, tense, fight-to-the-death encounter with the PCs and NPCs watching was when NEITHER OF US COULD HIT A DAMN THING !!!!  Instead of having a riveting fight the other characters were bored and/or chagrined at how their champion couldn't hit the broad side of the proverbial barn.
    If you've played for any length of time you know what I'm talking about, that combat where it feels like 20 turns go by and nobody can hit anything.  Swing and miss, not the one-sided "oh crap we can't hit the bad guys" or "we rock we can't miss."  No, this is the frustrating, painful, boring "neither side can hit the either even though we're standing still two feet from each other swinging massive two-handed weapons."  Dice are random, that's why we use them after all (well, not random per se but unpredictable, sorry, tangent again) - but the thing is that flat dice like a single d20 are even worse.  The odds of rolling a hundred 1s are the same as rolling a hundred 10s or a hundred 20s.  With multiple dice and that bell curve the odds of rolling a hundred 2s or 20s is way, way lower than rolling a hundred 11s.  They are not quite as swingy.  In theory at least, again I've never played a game long-term that used multiple dice, so this is theory - and it's pretty subjective since the unusual edge cases, like my wiffle-ball fight, are the ones that stay in memory the clearest instead of the typical fight where most attacks hit.  So all this is based on feelings more than any real need or reason.

    That said, let's see what happens when we switch dice.  I'm going to keep Advantage and Disadvantage as rolling 3 dice and keeping 2.  I'm also going to do this from a +0 to +16 modifier against the 6 DCs in the 5e SRD, just like the last table, so here goes...

Okay, let's grab a few results and compare.  First let's look at a +0 modifier, a beginning character with no attribute modifier and no proficiency.

Very Easy    64  80  96 on 1d20        85  94  99 on 2d10
Easy             30  55  80                      38  64  85
Medium       9  30  51                        7  21  43
Hard             1  5  10                          1  1  3

Okay, so the easy is a little easier and the hard a little harder.  Now let's look at a +2 modifier, so having an attribute bonus or proficiency but not both.

Very Easy    81  90  99 on 1d20        98  99  99 on 2d10
Easy            42  65  88                      58  79  93
Medium      16  40  64                      15  36  62
Hard            2  15  28                         1  6  15

Okay, so looking at Easy - with a +0 it's 55 and 65 with +2 on 1d20.  It's 64 or 79 with 2d10.  So 2d10 is not a big boost, but does favor the players over 1d20.  The funny thing is Hard where 1d20's 5 / 15 is better than 2d10s 1 / 6.  So this would make reaching for those really hard DCs even harder, and Advantage doesn't give that much of a benefit.  That kind of sucks.

    Overall, I don't think I really like this.  Well, let me amend that.  I still like the idea of rolling 2d10 for attack rolls, I think that would help take out some of the crazy swingy results.  But for skills I would switch to the regular 1d20.  Okay, so that was an interesting waste of time :)  Here's the regular 5e Odds table below, and you can find another crazy way to use dice in my post on constraining results to simulate skill.