Hard to say how the new expansion will change things without the entire set. The devs are pushing new deck archetypes so we'll have to see if they are strong enough to be meta.

I usually just netdeck from gudecks. Sometimes I'll slap together a deck for restricted formats by putting in the strongest cards and going down from there then swapping in cards to fill out the curve and cover what I'm missing, I mostly do it based on intuition. I pretty much just play in weekend ranked and tournaments and don't grind and practice decks.