Superior Training

[SlimeGuru42]

How about:
SUPERIOR TRAINING
Benefit: Choose a Simple or Military weapon with which you are proficient. While wielding the chosen weapon you may either increase it's proficiency bonus by +1 (to a maximum of +3) or increase it's damage die by one step. If the weapon chosen is a Simple weapon, do both.
Special: You can take this feat more than once. Each time you select this feat, choose another weapon.

The only simple weapon that wouldn't get the full benefit is the dagger, which most likely balances out.

 

[77IM]

That's... actually really good! My only reservation is that longsword winds up identical to bastard sword (+3/d10/versatile) while greatsword remains inferior to fullblade (+3/d12 vs. +3/d12/high-crit). This seems to be a generalizable problem, as the two-handed weapons improve more than the one-handed over the course of simple -> military -> superior.

Here's a fix for that, that is slightly complicated...

SUPERIOR TRAINING
Benefit: Choose a Simple or Military weapon with which you are proficient. While wielding the chosen weapon you may either increase it's proficiency bonus by +1 (to a maximum of +3) or increase it's damage die by one step. If the weapon chosen is a Simple weapon, do both. If the weapon is a two-handed simple or military weapon, it also gains a weapon property, based upon its weapon group:
Axe, Mace, Pick: Brutal 2
Flail, Heavy Blade: High Crit
Hammer: Brutal 1
Staff: Defensive
Special: You can take this feat more than once. Each time you select this feat, choose another weapon.

 

[eriktheguy]

The concept of this feat is good and I encourage you to go with it. The +1 to hit is unbalanced. Players that stack it with weapon expertise and a weapon that was already +3 prof will be slightly more powerful than you want them too. What you could do is sit down with any player that takes the feat and discuss what sort of training they want. Maybe high crit, light thrown, brutal 1, etc. Always make sure it is balanced for the weapon in question.

EDIT: oh, looks like you already did that

 

[Flipguarder]

It can become a huge problem with rogues who already have a huge bonus to hit.

Overall I don't really see the problem. You got a big hammer, you got a big hammer with a spike on it. It kinda makes sense that being able to use the one with a spike is gonna yield better results.

And on the other side I really don't see a reason to increase the damage of a sling over or equal to a throwing star.

Something tells me that some of the people who think this is an issue would find superior weapons useless after this idea was implemented.

just reskin stuff it makes things so much more simple than clumsy houserules.