Herrera can be effective in that position, but the thing is he more of a traditional #8, a Spanish version of Steven Gerrard, that was his position under Bielsa and now under Van Gaal. So tinkering with that to accommodate another player with a similar kind of overall box-to-box skillset (+/- a bit here and there) might not be the greatest idea in the world. He can play as a #10 as and when required, did so last season and at Zaragoza back in the day, but he is most effective in the #8 role. eg. For the Spanish U-21 team with Martinez at #6, Ander at #8, and Thiago at #10.
When talking of a prototypical creative midfielder in a central three who can help unlock defenses, it's more like an Iniesta or Isco type of player; or Litmanen for Ajax; or Sneijder for the Dutch national team under Van Gaal, who offer more offensively. Then again, Louis has stated that the Premier League necessitates a more pragmatic, defensively stout approach; so maybe he needs someone like Schneiderlin to provide added steel, and energy, and workrate at the expense of creativity. I don't have a fundamental opposition to the idea mind, it would be very balanced defensively, and quite similar to the one Milan had with Pirlo, Gattuso and Seedorf.