I don't understand why people who group up as a pair with a plan and good communication are allowed to queue up for games with solo players who only (sparingly) interact with the chatbox
Duo's are presumably friends who've played together often and automatically have an advantage against their solo opponents
even in Riot's rewards faq they say that if you don't have enough people to make a 5 man team 'too bad, go to the forums'
I'm pretty sure the matchmaking system works so that if you're duo queuing, you're matched against other duos or just higher ranked opponents; it's not perfect but the system works in a way that sees duos as an advantage, and thus will balance to compensate for that advantage, by matching with other duos, etc.
I've always viewed the biggest reason for allowing duos to be that a pair can prevent a surrender vote from going through. so for example if you're playing a promo that you definitely don't want to surrender no matter what, having a friend with you to turn down a surrender vote could help? reading the comment on adjusted difficulty though may mean I have to rethink that strategy for when I get there!
Duo's are presumably friends who've played together often and automatically have an advantage against their solo opponents
...And that's why they give an MMR bonus to the duo queued players to compensate for the assumed better teamwork/coordination/communication.
