The frustration that comes with Ranked; The promo's and match making, seems to be at a problem because of inherit ranking and queue timer.
What i think could easily fix these problems is turning it from it's current format of Ranks and Divisions to a Ladder system. Players play their 10 games as per norm, and gain proportionate amount of LP and then you enter a Rank of what correlates the amount of LP...
This would solve the frustration of promos as well as the possible match making system, where the system places you with others in a certain bracket (Players only between 1000-1200 will be matched)
I mean in general Silvers should only be Matched with Silvers but instead we have Iron's against Plats for whatever reason.
Personally i think it would be better system and less stress for those who may with 5 games in a row, get to their promos and lose two times out of 3 because of Bot lane. Nobody cares about Divisions, atleast not in lower Elo.. Silver 5 and Silver 1 are still Silver. Just like 1000-1499 are, but atleast you can bounce between Silver and Gold easier instead of the constant pressure of Promotion and demotion just because of a 'best of 5' that really just makes players play worse at times.