Riot should make a game knowledge test, like a "LoL IQ" test and require players to take it before posting on the forums. The results of this test, along with soloqueue rank should be clearly displayed whenever a user posts. This test could be updated and be required to be retaken each season. Each season's test a long with each season's rank could be displayed. Smurf/forums only accounts should still be required to take this test.
The benefits of this:
While it is possible to look up the rank of someone who is posting shit, this shouldn't be necessary.
Rank alone is a good, but not great indicator of how credible someone is.
A game knowledge test would add to this, and it would help eliminate the "but muh teams" excuse.
This may even cause the bads and the dumbs think twice about posting stupid game suggestions like:
"Give us loss forgiven if we have an afk"
...This would cause dramatic elo inflation and be abused.
"Remove the queue dodge penalty"
...champ select is part of the game, if a team losses at champ select then they're already at a disadvantage - unfair to dodge
"Nerf (insert name of random, balanced champion)"
...Please
"LoL should be balanced around the average player (as opposed to competitive)"
...And Basketball should be balanced around fat white kids. "Lower the rim to 6 ft so I can dunk too!"