A wizard/cleric can be a good build if you know what you are doing, especially if you are looking for a secondary divine class rather than a primary divine. My experience was that by concentrating on one side I got maximum benefit even without considering the Mystic Theurge class (blech
But then again, my character only had an Intelligence of 12.)
My motivation was that as a 3rd level cleric, she took the Brew Potion feat, and so I decided to make her a Getafix-like character. (Her patron deity happened to be the goddess of taverns, so that also fit into the theme.) Wiz 1 also gets you access to all those neat scrolls, so you can just pull out obscure little tricks from your backpack when they are handy. My plan was to eventually raise her Int to 13 and take her up to 5th level Wizard.
I don’t think that you need an exotic class. If it were up to me, the choice of classes would be determined by the campaign (e.g. the Iron Kingdoms campaign, which brings in Bodgers and Arcane Mechanics. IK also has its own version of the Ranger and Druid, although you need one of the magazines to get the variant druid.)