Lets discuss how to deal with flooded silver-platinum parties (usually silver is smurf).
First of all if you go with silver with platinum you should only face platinums. Put same rule than in higher elo. Why it is even different rule?
Increase ranked requirements to own 8 five level heroes. This will increase the time to make smurf, which will be good for smurfing and for new players.
Do not face for example bunch of solo golds vs platinum with smurf silver. This will lead to lose for solo team. Instead face platinum teams vs teams always. Teams have good synergy.
Increase newly ranked account mmr more faster so those good players wont stay in low too long.
Make solo leaque so that as solo player I wont face parties.