I would agree that the Guardian theme's shield ability isn't meant to be used to protect the guy who has the ability. I can see both sides about the RAW but I would rule based on assumed intent there.
As for intoxication, I didn't notice it before but I do think it's an issue for the wizard. Maybe the rule becomes something like "You have disadvantage on attack rolls, and creatures have advantage to saving throws against effects you cause."
Regarding the reaction rules, obviously they need to be clarified. I also spent some time working out these rules because of the L&L article that suggested using a reaction would spend your next turn's action. Where I came down is that there are only two reactions mentioned in the playtest (someone correct me if I'm wrong): the Guardian's ability, and readying an action. The Guardian ability wouldn't use your next turn's action, since it doesn't say anywhere in the rules that it should, and it's situational enough (you have to be within five feet of an ally who's getting hit) that it won't come up constantly and thus be spammed and broken. It never got used in my playtest, frex. This would actually also be an argument against it being usable on the Guardian himself: in that case he could use it every single turn almost guaranteed, making it very powerful.
Readying an action, on the other hand, wouldn't use your next turn's action, but rather your current turn's action. That is, it would work like it has in 3e and 4e-- instead of taking an action this turn, you "save" it for later in the round, then when it goes off your place in the initiative order drops to that spot. I believe this is even addressed in the playtest packet. So readying an action lets you take a reaction if the definition of reaction is "doing something on someone else's turn," but it's really just a readied action as we know and love them. I expect we'll see more powers that grant reactions in the future, some that use up next turn's action (Opportunity Attacks, perhaps) and some that don't.