You only get that dodge bonus if you wield a longsword or Rapier and only if you wear light armor. Given the race and feat requirements the earliest a Duskblade will be able to enter the Bladesinger class is 7th level, (around the time a multiclass fighter/wizard will be entering).
At this point a Duskblade can already wear Medium armor w/o ASP.
Going with Bladesinger a dusk blade will miss out on:
5 spell casting levels
Increased power of Arcane Channeling
Increased power of Spell Power
Will lose one use of the quick cast power, assuming an equal balance level between a Duskblade's Quick cast power and a BladeSingers' song of celerity. Frankly I think the Quick cast power of a Duskblades is better than the Song of Celerity.
a Skill list that does not really jive between class and PRC.
The only benifit I see is that a Duskblade/Bladesinger combo would have a much better reflex save then a Duskblade by itself, and the Song of Fury power which is easily duplicated by the spell Haste.
As an aside why is Haste not on a Duskblade's spell list. If anything strikes me as the ultimate buff spell for a gish type character, being able to cast Haste is it.