Sacrifice the character or the story?

[S'mon]

I am always the thinker... the leader.  

Hi - to me, it seems that thinker & leader are traditionally two different roles - Arthur & Merlin are very different archetypes.  Good leaders benefit from having good thinkers to advise them.  Why not take the advisory 'Merlin' role with your PC - let the party leader know your advice in-character, but allow her to make the final decision? That way she'll be in possession of all your facts.  Playing a PC who never makes decisions _or_ offers advice sounds more like playing an NPC cohort/sidekick than a real protagonist to me!  The trick to doing this is to offer your advice cautiouly, as being your interpretation of the facts, not as a demand for action along closely prescribed lines.  "It seems to me the Fooramfar must be connected to the Dalweezil, so interrupting the Katomart might..."
rather than "We must interrupt the Katomart!  The Fooramfar-Dalweezil connection depends on it!"  :)