TL;DR: Game mode similar to One For All, but instead of picking which champion to play, the team picks which Faction to play as, opening up the champions of the particular Faction to pick.

Abstract

Players on a team choose which Faction they want to play as / pick champions from. Each Faction has a specific Bonus, for example (based on some champion passives):

• Freljord Bonus
• Each auto attack or ability after # seconds out of combat freezes the enemy, slowing their movement speed for # duration.
• Shadow Isles Bonus
• After # seconds out of combat, cloak is gained, providing stealth from regular wards for # duration.
• The Void Bonus
• After # seconds out of combat, a temporary shield is gained, protecting from the next attack or ability.

Each Faction has each role needed for Summoner's Rift, if necessary.

Format

• 5v5 on Summoner's Rift
• Each player can ban one champion. Only two champions per Faction can be banned.
• Each player can pick which Faction they would like to play. Majority vote picks the Faction, however, if the vote is tied, it is randomized between the decisions (similar to One For All).
• Once vote goes through, all champions related to the Faction will become available to the team. Champions related to the Factions listed in the links below.

Factions:

• Bandle City
• Bilgewater
• Demacia
• Freljord
• Ionia
• Mount Targon
• Noxus
• Piltover
• Shadow Isles
• Shurima
• The Void
• Zaun

Options for Riot

~~ ~~

Missions:

• Win # games playing as [Faction] Faction!
• Play as each Faction once!
• Win # games using (new) [Faction] Faction icon!
• Kill champions of an enemy Faction # times!
• Defeat a Faction rival to yours # times!
• etc.

Mission Rewards:

• Blue Essence
• Icon Upgrade
• Faction Orb
• etc.

Store Items:

• Faction Pass (Faction Orb, (new) Faction Icon, Extra Missions, etc.)
• Faction Orb
• Faction Icon
• Faction Border
• Faction Bundles (Champion, Skin, etc.)

Thoughts?

Please let me know what you think? Obviously, this would need to be fun for the players, not a ton of work for Riot, as well as profitable for them. As well as avoiding burning out players, giving the game mode an option to become permanent(?).