Everything looks good, if not nearly enough to revive GvG without the overhaul of the RP shop being substantial.
Really like the idea of a short window of prep time before the start of a conflict, most of us don't sit at our computers and wait all day and in my experience most players will defend themselves if given the opportunity. Waiting for the most opportune time to strike is a valid strategy in any combat. Thankfully, this is a game and I think giving the time to prepare and organize to defenders would be for the better enjoyment of the casual playerbase even if it is not in my best interest.
2 days or 7 days offline doesn't really make a difference to me, level ranges being expanded would help negate some of the drop off in active targets. Guild level and age requirement looks fair as well.
On a different note, I'd like to see an opt-in version of GvGs. Keeping the current system in place but adding a parallel system for guilds that wish to compete for higher rewards, with more risk. Like XP loss, increased gear damage, etc. Just a pipe dream considering few guilds would partake, but I figured I'd post it here anyway since navigating to the Forums was such a pain in the ass now.