Geminids definitely has potential. Casting value 7 (obligatory "not great, not terrible" meme), but 18" range which is nice. Solid damage (no trigger roll required), nice debuffs. Troglodon Oracle can cast his spell from the edge of the board, add Knight-Incantor with Everblaze Comet for more out-of-denial range goodness. It's not going to break the meta, but currently I am looking at something like this to keep me interested in playing.
Lifeswarm will be a great pick all around, with its ability to bring back dead models it can be slotted into almost any list.
Regarding tournament play, do you typically roll in which realm you are playing? Might actually become interesting with the bonuses for the Endless Spells.