Until summer means before september 1st :)
It's a matter of translation and cultural nuances.
If my boss told me I had until 2 p.m. to finish a task, I wouldn't stroll in his office at 2:59 and say "hey, you told me I had "until 2."
To me, through summer would have meant till around mid- to late September (if someone gives seasons as their schedule, I assume they're thinking solstices as the marks). That's why to me "until summer" means they plan to have this stuff implemented by mid- to late June.
And I don't think it's absurd to assume so. Yoshi-P has said several things to indicate such thinking; such as this is going to be the largest patch yet, that for the past several months they've had multiple teams working on varied content (much of which is waiting for the initial battle changes).
Either way, we're finally getting what we've been waiting for, and this community can finally start to form a definitive shape.
Ultimately, it was vague on purpose. If all this stuff is ready for 1.18, then the devs look like heroes because they delivered on a promise. If it's not, then they just come out and say that the plan never was for all of that to be ready that soon. Edited, May 22nd 2011 4:00pm by Sephrick