For me? It usually starts with "who do I like", then ends with "but what do they do", and "how do they do it". Only consider the first question, and you'll probably have some degree of fun optimizing around them.
I've been out of this meta for a while, but unless your deck oozes with advantage generation, you should consider having a good high base Attack to consistently rely on, both to keep you alive during your opponent's turns, and to make it easier to hit face during your turns.
Shannan sucks. While Divine Blade: Balmung is an amazing way to fill your hand with Evades, remember that you also reduce your hand to nothing BUT evades for Shanan, while also requiring a big hand to get the most out of his skill. Because of this, it's a "win more" thing. Promised Sword will rarely come into use, unless you're either buffing the shit out of the untapped unit, or only using it to clear rabble, in which case, it's on your opponent to keep things out of the Front Line.