Especially with all the new classes and races, it may spice up the game if the player could control more characters. On the other hand, it would be too easy for a party of, say, 6 characters to learn all the available skills between them. There is, however, a solution: my suggestion is that the player would control 6 characters, while keeping only 4 adventuring slots. Thus, each time the player will start on a quest, she'll have to choose which characters will form the party. There would be plenty to consider: will there be a lot of monsters or is it more of a puzzle, are the skills of our thief needed on this trip, will the party be confronted by might or magic, is it in a dungeon or in the open, is it closeby or does the party need to travel, is it a promotion quest, etcetera.
While four characters are adventuring, the remaining two can guard the homestead, train up, send and receive messages, talk with ambassadors, heal, look after the dragon whelp or play arcomage.