Shattered Kingdoms

Do you mean weapon size in comparison to the size of the character? Such as a human wielding a size large or small weapon, or simply a sprite wielding tiny weapons in comparison to a centaur wielding large weapons?

Either way I don't think it makes a huge difference if any. I know one time with my mercenary about a year ago I was in the Iron Citadel, and my void spear went kaboom on a NPC I was fighting. I picked up another battlespear while in the citadel however we had no sorceror to resize it, so I did the rest of the run with a size large spear as a half-elf, and still recieved all four attacks a round.

I'm fairly sure the size of the weapon will affect damage and accuracy however, weapons to large for a particular race do more damage, and have a penalty to accuracy, etc... There was a post a very long time ago that detailed what is penalized when wearing armor or weapons to large or small for your particular race. Before that everyone just ran around with weapons one size to large because they dealt more damage, and had no noticeable drawbacks.