Queue into already existing 4v5 match
We've all had 4v5s. We've all had a LOT of 4v5s. What if there was a way to stop 4v5s once and for all?
Enter "Queue into Existing Match" option.
Basically, when you queue for a match, you can queue either for "New Matches Only" or "New & Existing" -- as well as queueing for your two roles and/or Fill.
Queueing into "New Matches Only" does exactly what current queue does.
If you queue into Existing, when the queue pops, you have a time limit (15 seconds or whatever the current timer to accept a game is) to decide whether you're going in. Since there isn't 9 other people who get sent back to queue if you decline, there's no penalty for repeated declines.
It'll show the tab screen, i.e. what you see in-game when you press Tab. That'll be the entire game score -- tower counts, dragon counts, KDA, champions in game...with the one you'd be subbing in as (and their role) marked.
Now, how we calculate LP and MMR off victories and defeats for the original summoner (OS) and substitute summoner (SS):
All summoners (5 on the enemy team and 4 on the allied team) other than the OS and SS in question get whatever the game result is. Gain LP/MMR on a win, lose it on a loss, at the same rate they would have if the leaver didn't leave.
OS is always assumed to have lost. OS records a Defeat for the match and loses LP and MMR as if they lost the game.
If SS's team wins, SS gets a boosted amount of LP (but keeps the same MMR effect of a match as if SS played the match from 0:00). However, Existing games cannot count as wins (or losses) towards promotional Best-of-3 or Best-of-5 series.
If SS's team loses, SS loses a reduced amount of LP for the loss (but keeps the same MMR effect of a match as if SS played the match from 0:00).
Games enter Existing Queue from when "Reconnect" or "You have been disconnected for inactivity" pops up, but not the "Attempting to Reconnect" that appears in-game if you suffer a momentary disconnect.
The boosted LP gains and reduced LP losses are to encourage players to queue into existing games.