2017 suffered a lot because these shows kept lollygagging. Honestly, both these series should have already happened by now. But 2018 will have Fairy Tail, Index and SAO again, and all is right with the world.
If you really wanted to make my day, you would announce Papa no Iukoto Kikinasai! would be adapted in full, or something off the wall crazy like that. This stuff is just touzen, naturlich, atarimaida, obvious, inevitable. I'm glad the anime industry hasn't gone mad and abandoned their very best franchises out of pure spite, but that's the bare minimum of sanity. It's not something to get joyous about. Rather, I'm still angry that it took years to announce the two most brain-dead, obvious, even-a-two-year-old-could-make-this-call decisions in the entire industry. What on Earth were they waiting for?
No matter how much Index they cover in Season 3, it won't be enough, because the books just go on and on. So it won't be removed from my wishlist even with this announcement. SAO is off my wishlist though, with a new season of Kyoukai no Rinne requested in its place. It's nice to finally have some wishes granted. If they keep making announcements like these, 2018 will make anime great again.
As promised, SAO is now the #1 anime of all time. Index/Railgun has moved up to 13th place. The lack of sequels were holding back both of these shows' potentials, but Sword Art Online's most of all.