No master is too difficult if you are keen to learn the game. On the other hand, if you are looking for an easy-to-pick game for casual play, then probably every master is too difficult. Malifaux demands a certain degree of devotion, otherwise it's hard to have fun with it. At least that's what I've learned teaching new players recently. Responding to your question more directly: masters who can act independently from other models (i.e. don't rely on their support/are less synergistic with their keywords) are as a rule easier to play for the first few times; also, I find beaters and summoners easier to pick for beginners than support- or disruption-oriented masters. However, since summoners require a lot of purchases it is usually not recommended to begin with them. It means that you can probably cut off from your list following masters: Seamus, Molly, Jack Daw, Pandora, Zoraida, the Dreamer and Colette. All of them (maybe except the Dreamer, who is pretty boring but has poweful keyword) are super fun to play once you know what you're doing, btw.