Well, to answer OP: I am sort of hyped about the expansion.
It kinda saddens me that the first thing people now say when seeing a card is "Odd/Even Class can now play this!!!" It's just sad when the community is already barricading half of their own collections for the sake of forced netdecking introduced in a previous expansion.
"Odd Warrior cannot run this.", "Odd Paladin doesn't need healing or immunity.", "I can sense this being used in Odd Rogue.", "Might see some play in Even Shaman in Wild." Oh wow, nice of you to already cut down half of the incoming cards before they come out. Back in the day, they were filler if they were bad. Now they are just filler if their cost is not the mainstream class cost! What a time to be alive.
Genn and Baku have pretty much neutered the Loa playstyle before they even came out, just because most of their spirits do not share a cost with them.
Still, I am hyped for those 15% of people who might not be so eager to leash their own deckbuilding by the balls and who may actually do something new during the first week. As for the rest, well, if I see Baku or Genn in the first few days I'll give them the instant-concede (it's probably the win they are after anyway).
I mean, people who restrict everything to Odd / Even are just not seeing the potential of cards and deckbuilding in general. It doesn't have to sadden you, just build the decks that seem coherent to you, try them out, tweak them, and eventually come up with original stuff that'll wreck these Odd / Even netdecks like taking candy from a baby.