Eldritch_Lord
Adventurer
You are saying it should be initiator level 11(warblade +3) + 4(half swordsage level plus 3) + 8(mo9 level plus 3) = initiator level 23 at 17th level?. That is clearly not balanced. Not does it appear to be the intent of the bloodline mechanism or the intended way they meant for initiator levels to accrue.
Not the intent of IL, probably, but then, this is WotC we're talking about. It is, however, the intent of bloodlines:
SRD said:Similarly, the stunning attacks of a 3rd-level monk with one bloodline level have a save DC equal to 12 (10 + one-half class level) plus her Wisdom modifier, since the bloodline level is treated as if it were a monk class level when calculating the save DC. A 3rd-level monk/3rd-level sorcerer with two bloodline levels would be treated as a 5th-level spellcaster and a 5th-level monk for determining level-based abilities.
They affect every class, not just one class. Every class contributes its class levels to IL, and it's a level-dependent value, so every class adds ½(class+bloodline) to IL.
As to the balance--no, of course it's not balanced. That's why all the "powergamers" and "rules lawyers" over at CharOp and that I know IRL (myself included) say not to use bloodlines with ToB classes or at least rule that it only affects one class, as you have done. Under those circumstances, it's just fine, but by default binders and ToB get wonky when bloodlines are involved.
As far as why anyone would take 3 bloodline levels? No reason at all, except for the bonus feats, skill bonuses, spell-like abilities, and stat bonuses that come with all the major bloodlines.
Only some bloodlines are worth it, and only for some classes. Three +1s to set ability scores, a handful of weak bonus feats, and a few skill bonuses don't always make up for three full levels of stuff. The storm giant one might be worth it for a barbarian, for instance, as it provides Power Attack (which you were going to pick anyway, so you get another bonus feat), bonuses to Str and Con (yay more rage!), water breathing, and freedom of movement (screw you, spellcasters). A rogue, however, usually gets more skill points in those three levels than the skill bonuses grant, which he can put where he wants, and he can't really afford the lowered HP and probably doesn't like the reduced saves.