I always, when either making a class, a varient for a specific campaign, or anything, i try and make whatever im making strong, but not too strong, playable, interesting, and possibly appealing to the player. now, on that note, i see the pros/cons here vs the bard
PRO: More specialized, focused
CON: bardic knowledge, bardic music
PRO: different applicable sizes and types of 'puppets'
PRO: interesting abilities
CON: Inspire competence, inspire courage, fascinate, contersong
PRO: perform isnt nessicary
the last bit, is very true. no where in my brief reading of this, is the nessecity to have ranks in Perform.
however, on optimizing, id go for a prestige class that happened to require 13 ranks in one skill(such as Craft, or Perform) and 13 ranks in diplomacy, taking it would allow me, in a sense to have particular better rolls on Craft(puppet) and Perform(Puppeteering) or whatever the correct term would be
i also find, using a bard, a couple well placed enchantments, and a couple permanancys, plus conversing with the DM, could make, more or less, an awesome Puppet that can talk, fly to an extent, climb walls, shoot rays of fire out of its eyes and whatever else I can think of.