GOAO
i like oras quite a bit (much more than SM or SS), despite calling it a clusterfuck. it is my home tier, after all.
My main gripe is its raw power level relative to SM and new BW, an issue I feel that when combined with flexible trapping, really pushes teambuilding constraints to their limits.
For example, the need to pack untrappable Fletch/Mienfoo resists, the unviability of defensive cores in general (gasp!), etc.
To elaborate, take for example, fighting checks - Foongus (trapped by Goth unless Worry Seed, which still loses to SubRest), Spritzee (trapped by CM Goth), Snubbull (trapped by LO Dig after chip), Cottonee (trapped by LO Sludge Dig), etc are all trappable. It's extremely easy to tailor a team to keep momentum and double up on offensive breakers while relying on trappers to remove key threats - it's why, if you look at my team dumps, you'll see heavy emphasis on Cottonee + threat + trapper teams. Trapping can be applied to remove pretty much every defensive answer in the tier in some way - Mag for all steels, Goth for anything "weak'', Dig for most offensive threats...
That said, trapping provides a necessary way to break fat structures in ORAS - no one wants to play against some variant of Porygon / Foongus / Staryu / Chinchou / Fighter / FerroSpritz etc every match. There's also slight counterplay to trapping by using Scarf Dig, Trace Porygon, Pursuit to remove opposing trappers... but it heavily favors the trapping user in terms of playmaking or requires very specialized teambuilding design to remove trappers by stacking similar mons + aforementioned counterplay.
There's no good way to remove trapping from ORAS - in my mind, it is synonymous with the tier as a whole. Hence why I called it a clusterfuck.
It is a tier that requires good planning, good teambuilding, and excellent play - in its current state, a single wrong move will cost you the match every time. A player with poor matchup must also understand exactly what plays they need to make to win, and execute flawlessly; many times midgrounds are not an option.