I agree with all comments/replies to your question. To me the most important part of raku is the post-firing reduction. As Marcia said, a copper based glaze can give you so many iridescent colors and luster if the pot is removed from the kiln and placed in the reduction can. If you want to let it cool gradually, do it in the reduction can with the lid tight so the glaze doesn't re-oxidized--'cause then you'd just have a green pot.
Also, try under-firing and/or over-firing to get different effects with the same glaze. What a difference of two minutes either way can make in the outcome.
So, if you don't like the outcome, just re-fire (maybe even layer on a different glaze) raku is fun and surprising, so enjoy it.