While theres going to be lots of 'trolling', theres also going to be lots of 'innovation' where unconventional supports (and champs in other roles) are going to be popping up as they make use of new runes in spicy ways (in some cases people thinking they're trolling may actually be onto something without realising it, and sometimes people thinking they're clever innovators might just produce a disaster).
Both GP and ez support with klepto are things I've heard are not as awful as season 7 experiences might have trained us to believe for example.
Still, people lose their sense in preseason since they forget preseason mmr can still impact their placement next season, and then when next season starts we'll get the usual ton of threads featuring people raging about how they got placed more than a full tier below where they ended despite going 10-0 in placements.