The bastard sword is everything that is wrong with the Dungeons & Dragons style of weapon mechanics.
The bastard sword was put into the game because they needed a sword between the longsword (d8) and the greatsword (2d6 or 1d12, depending on the edition).
But then they also needed a style of sword between one-handed and two-handed...
Well they put in a bunch of rules and regulations and exotic weapon proficiencies, but as it ends up, the bastard sword was always the best bang for your buck. If you were a fighter and you weren't wielding a bastard sword and heavy shield, you were a fool.
I'm gonna get a little technical here, but bear with me. These kinds of breaks within a game rule module (i.e., the weapons system) results from a failure to define the system's "space." See, the vast majority of weapons in D&D, until the bastard sword, were either one-handed, or two-handed, never both. Somewhere along the line, someone decided to give a mediocre bonus for wielding a one-handed weapon such as a longsword in two hands (strength bonus plus a half, for instance, or the flat +1 damage in 4e, etc.). But even that addition was okay, because it didn't muddle the two categories in form or function.
Then the bastard sword was born out of the two-category wedlock (pun intended) and everything went down hill.
So here are the dimensions of your "weapons space" that you have to define when you are designing your game's weapon system:
-First: The damage dimension.
D&D did this worse than just about anyone. 1, 1d3, 1d4, 1d6, 1d8, 2d4, 1d10, 1d12, 2d6, 3d4, 2d8....it's garbage. There is no need for this. Not to mention that a dagger (d4) is just as deadly as a greatsword (2d6) when used by the right person in real life and in fantasy literature and film, so why screw them in your system?
No, you need to figure out 2-4 serious damage categories for your weapons and not break them. I use 1d6 (one-handed) and 2d6 drop the lower die (two-handed). This makes every weapon equally deadly on a good hit, but still gives larger weapons higher average damage. You could also do something like 1d6 small melee, 1d10 large melee, 1d4 small ranged, 1d8 large ranged. This balances the range-damage dichotomy pretty well, and gives you something to show for that extra hand you need for large weapons.
-Second: The proficiency dimension.
I like to give my players bonuses. If you are giving someone a penalty that isn't in-game and situational, you need to take a long, hard look in the mirror and ask yourself if you need help.
Why would I play a game that takes time to tell me all the things my character is bad at? No. that -4 "non-proficiency" penalty from 3.5? That shit needs to GO. And those countless proficiency bonuses from 4e? God, I don't know what's worse, number inflation, or random number redistribution to make things look more balanced when they are mathematically the same as before.
Here's what I do: each weapon has basic properties, trained properties, and mastery properties. If you have no proficiency with the weapon, you get the basic package when using it, and that's it. No penalties, no financing charges, no early cancellation fees. You just get vanilla, and that is always better than nothing.
You trained in that weapon though? Well, now you start getting some extra cool stuff on top of the basic package, like the ability to counter attack with a rapier when your enemy misses you badly, or the ability to circumvent shields when you swing your flail, or a sweet little bonus to AC for knowing how to use that bo-staff right.
Mastery works the same way, you get even more cool stuff, like the ability to do grapple maneuvers with your greatsword (like you're supposed to when you're good with one), or more devastating critical hits with your battle ax, or the ability to throw that greatclub....okay, well, maybe not that last one, but you get the drift.
Third: The accessibility dimension.
Lastly, you have to figure out what groups you are gonna package these pointy suckers into so you can easily point certain classes to their early weapon choices. For me, Simple, Light, and Heavy do the trick. If you can picture the class walking around with a greatsword, they get all three groups. More subtle, but still martially focused? Simple and light only. Wizard types that usually eschew martial combat? Simple only. Done.
Now, another important feature is character fluidity. I don't want to prevent my rogues from wielding greatswords if they want to, so there's no sense in putting up barriers to that kind of stuff. In fact, a simple rule for how to gain training or mastery in a weapon (note: simple rule, not simple in-game task) is highly recommended.
Dungeon World grants XP through misses in combat. That's not a bad idea for gaining weapon training. Think about it.
Until next time-