Mourn said:
That's like saying all Craft skills should be merged into a single one... after all, beating a piece of metal into a breastplate and beating a piece of metal into a sword are more similar than playing a flute or trumpet.
However, I have to buy Craft (weaponsmithing) and Craft (armorsmithing) separately, but I don't really see any complaints on that being limited. After all, if you want to play a Fighter than maintains his armor and weapons himself (which a good fighter should be able to do), you have to spend up all your skill points and not be able to pick up other things, such as Intimidate, Ride or Jump.
The change is bad for a number of reasons.
Neither the new nor the old system are particularly realistic. That is OK, since the game system really isn't realistic either. Perform with flute and trumpet do help each other, since you (hopefully) develope an ear for music and a sense of rhythm. Since there are a lot of musicians who can't read music, I will not include that as a synergy.
The realism arguement also falls a little flat when you look at the rest of the D20 system. Someone who is an expert armoursmith isn't any good at blacksmith or jewelry? They can't pound out a horseshoe or fix a metal clasp on a ring, but they can make custom fitted full plate?
The D20 skills are mostly broken down by where they give you a game-mechanical advantage. Armorsmith and Weaponsmith are two different skills because they allow you to fix or produce two different types of equipment that are important to characters.
This is not really true of Perform.
The Bard class needs to have a high skill in one type of performance in order to use a class skill. There is no difference in the results between a bard using Perform: Wind Instruments and Perform: String Instruments, they have the same capabilities as far as Bardic Song is concerned.
That isn't to say that a Bard doesn't need more than one type of Perform skill. If the GM includes magical instruments in their campaign (such as lyre of building or pipes of the sewers), the Bard suddenly requires different perform types to use two different magical items. They can use a magical staff (with UMD skill) equally well regardless if it is a staff for a wizard or a wand for a paladin, but if they don't have enough ranks in that type of instrument they can't use it.
I think it was a mistake to make the skill more specialized in the name of realism. D20 isn't a very realistic system, you shouldn't be looking for fine grained skill definition like that. Instead, it should be based on what game-mechanical benefit it is to have it as two separate skills vs. a single skill.