A ducal+ title is a Duke/King title. Make sure all of your vassals are counts, so you don't need to take care of the pesky electors. Having bishops as vassals is better because of the open succession of bishoprics as well as the investiture mechanics so they don't inherit claims from their predecessors, since they almost always don't have any family. There are a lot of bonuses that can be gained as well, such as the paragon of virtue ambition, which gives a +50 opinion provided you reach 500 piety. To make someone a vassal simply go to their diplomacy screen--->grant landed title. To make someone a bishop vassal with free investiture, go to the religious tab(cross) and click appoint successor under the bishopric you want that person to take over. After that, simply wait for the current bishop to die/assasinate them.
Ignore all of this. It's just a gamey way of playing.
There's nothing wrong with gavelkind. It's easy to deal with the lost titles when you're small, just revoke them all or imprison/banish everybody. Try to get a duchy title before your count dies.