PSA: Wait to jump on Assassins because of the new Runes
They've always been top tier during every preseason and usually (not always) fell down as we got more used to the new things, some would also say that Assas have become useless with time passing and tweaks being done.
From what I saw, the new Runes brought a really visible spike in earlygame power, I can surely say that for mages that use Arcane Comet, I've never had an easier life against a Zed as Xerath as now. Give it some time so that we figure out the new system and let Riot do the statistics.