We haven't had a new faction since the introduction of Mount Targon back in 2011.
Plus with the re-structuring of the Runeterran map, maybe we could expand on that and add a new city-state or give greater emphasis on a mostly unused location, like the Voodoo Lands for example, or the Plague Jungles. Both have only one representative in the forms of 
and 
respectively. Or perhaps Kumungu may get some more attention, as they only have 
and 
Well, we already got a new faction this year, aka: SHURIMA (before that none of those champions had connections)
I wouldn't be surprised if they do it again with a new faction
Riot should expand the already existing factions before making new ones. Mt. Targon has only 3 and little is really known about it.
Also isn't 
in the kumungu jungle?
They can bring 
and 
into this world as a new faction because as of right now they are some off world being summoned by summoner who does't exist anymore. Although I am kind of afraid when they get updated they become myth and legends type of character like 
and 
.
No, there are enough. They just need to finish their retcon with all the places and regions within Runeterra. They have plenty of room to release a couple to half a dozen of champions per faction. As you said, Plague Jungles and Kumungu could have 2 or 3 more champions. We could have another one from Shurima. There is still an old sage trope spot that needs to be filled. Reworked champions could become more amazing champions. There are subfactions within faction such as the Houses in Demacia which all should have at least a champion (House Spiritmight doesn't). You never know what's lurking within Noxus and Zaun. Piltover could use more champs. Doesn't hurt to release another yordle champ. And a few more factionless champs cand be released. Could get one of Zed's students.
Or a released demon from one of Thresh's artifacts (when he was alive).
I think we've got at least another year and a half's worth of spots in Runeterra which can be easily filled with new champions.
We still know very little about a lot of the existing Factions. We have the most backstory on Bilgewater and SI due to events.
(Also very minor nitpick, Mt. Targon isn't new. It was just called "Mt. Gargantuan" before Leona's release, and the tribe was called the "Stanpar" instead of the "Rakkor", because that reference had to be as obvious as humanly possible.)
I wouldn't be against a secret mountain in the middle of the ocean near Ionia where all Celestial activity took place. It would be a cool place to link some old current champion lores to (
) and create new champions from there.
We could also do a cool Glade event since Lulu is the only Glade character.
Annie is technically Noxian. Her parents were from Noxus.
As long as it doesn't suppress their ideas/creativity, I kinda want Riot to clean up the current factions before moving to new ones. :P
