As fun as Wizard 101 and Pirate 101 are, they still need a few more siblings to help round things out a bit. I like the Steampunk aesthetic of both games and would have no problems with future games continuing that trend. That all said, there still need to be more games for diversity's sake, as fun as the games are they really don't offer much in the way of diversity.
A while back, I was reading the KingsIsle message boards and came across a comment about someone wanting a Ninja 101; I don't recall what their moniker on the board was though. As for me, I came up with 2 games of my own for having fun in the Spiral. Those games are what I call Mechanist 101, a game that takes a more technology-centered approach and is built more around player creation than acquisition, and Spiral Adventures, which is a game designed to be more easily jumped into due to you just taking characters you already have from the 101 games and use them to adventures with friends.
Mechanist is an idea built around player creation so most of the gear you would normally is replaced with Schematics, better known as blueprints, for making equipment, weapons, vehicles and some mounts. I actually came up with 3, possibly 4, types of mechanists that could potentially be played by the players. Chemical Mechanist, a type of Mechanist that specializes in the creation of devices and items with chemical components; and Roboticists, mechanists that specialize in the production of mechanized companions and mounts/vehicles; Arsenal mechanists, Mechanists that specialize in the production of weapons and combat gear; and Artificer, a mechanist that is focused around recreation of ancient technologies and replicating magic through the use of their devices.
Spiral Adventures is a bit more straightforward but requires a few more installments in the 101 to work really. The idea is to take your Wizard that you really like, have a friend take their Pirate they really like, and whatever sorts of additions to the 101 series there are, and have a grand adventure with them all.