You have to remember that just because some things were not mentioned in the video doesn't mean they won't get any lore. Look at Kayle and Morgana: yes, they are marked as related to Demacia but their teasers look hella Targonian so we'll most likely get some Targon lore. Bandle City will provide some stuff on the Spirit Realm, and hopefully on magic in Runeterra (as teased by ThermalKitten). Then we'll have Mordekaiser, who'll bring some lore on the Shadow Isles and dare I say Noxus (since he'll probably want to take back the Immortal Bastion). Following that we'll have the next assassin champion, who will also bring some lore along with him.
And THEN (or rather, before the last 2 I mentioned) we have the next roadmap, in which we'll learn more about the incoming champs and VGUs, that is to say, some more lore. And we also have the Zed comic!
Don't worry buddy, we'll get lore this year. Not all champions will benefit it of course, but still. Seeing what they've done in 2018, I doubt 2019 will be a let down.