such all champions tend to be viable
hell no.
Many people have that wrong impression as they only play dominion as 'fun' mode, giving a fuck on strategie or what ever.
The vast majority of players is in low-elo-dominion, and the mode is more played like deathmage there.
In higher elos, you soon notice that there is a meta, and the number if 'viable' champs is smaller than on rift.
The atmosphere and so on is mostly based on attitued.
Back when i started playing lol(end of beta), I haven't seen alot toxicity, as people played mostly for fun rather than competition. There was not much meta, and no one gave a fuck which champs was taken where.
As the game and with it the playerbase evolved, things changed on the rift.
Same with item builts. Back in the days, people were experimenting way more, beeing open to things.
With the uprising community, especially with streamers, guids and E-sports comming out big, the players were more streamlined. They prefer the easy way and follow popular streamers or guids, or try to copy proplayers instead of makeing up their mind.
Befor a meta established and those 'paragons' became so easy to find, people did HAVE to make up tehir mind as there was noone telling them what to do.
And that's basically the dominion situation, There are few streamers or guids for domninion and no e-sports scene, and no ranked.
As a result, most playewrs play it for frun instead of competition, and they just screw around and try out stuff as there is no 'source' of how it's 'properly played', while only few really have a more competetive spirite in dominion and seek to optimizr their picks, builts and strategie
And as a side note, kills matter just as much if not more in dominion.