How effective is it to boost your ranked league by playing in normals?
Two seasons ago, I was in Bronze III.
After being horribly frustrated trying to escape Bronze as a support main, I didn't complete my placements last season and just played normal draft games as support.
This season I got over the whole Bronze experience and decided to do some ranked. After winning 6/10 of my placements (all support), I was pleasantly surprised to find myself in Silver V, meaning that I got promoted three leagues without having to risk promos with bronze players.
I'm pretty sure winning 6/10 placements isn't the only reason I got promoted that far, so my performance in last season's normals must have been good.
How effective is it to try to get ranked boosts by not playing ranked games? Promotion series are kinda annoying.