promos and toxicity should riot eliminate promo series.
one of the biggest reasons i see for toxicity is "promo pressure" even with the new promo helper. players in promo series are compelled to play out games where they would have normally dodged due to a champ select troll. and when you're in series. getting a troll or bad player hurts all that much harder. and further adds to the idea of "elo hell" puts people on tilt. and makes them more likely to be edgy during a closer game. because they are desperate to win.
EDIT. original post got deleted for being in the wrong board. because the mods are idiots