I didn't mean just wait a few matches, I meant like couple of weeks. You can still do ranked matches and raise your ELO, but won't be able to get into the next tier until you complete the series of matches.

Limiting the number of ranked matches won't stop players from playing Toribash just because the next matches won't count towards your ELO. They'll continue to play for TC / fun. Majority of players do not even care about their ranks, this is just something for the minority of players that actually care about a number and the limitation is just there so they don't go overboard and farm. Surely waiting a day to do another 10 ranked matches won't hurt so much would it?

The resetting of ranks won't be useless, because as I said there could be an annual event put in place for this where players compete against other players in the same tiers for a prize of some sort.
Small prize for the lower tiers (not small as in low-priced items/small amount of TC but small as in a medium-priced item/s) and larger prize for the higher tiers. Since it would be a yearly thing the large prize could actually be a large prize like 1mil TC or something, just an idea.
The demotion thing wouldn't be demanding so that you have to play, but if you want to be rank 1 then you should at least play occasionally.. (note: you don't have to play if you don't want to)