I'm playing the Omega Ruby romhack 'Rutile Ruby' having concluded with Renegade Platinum, and it's some horseshit.
Random trainers have their one or two nonsense creatures replaced with full teams of six, probably featuring ideal EVs, IVs, and natures, too. The level scale is adjusted so you're facing off against level 100 'mons by the eighth gym, and training reserve pokemon when you get stalled by one of these random difficult trainers is made more difficult still that they're usually not worth rebattling simply because half of their strategy is to wall you out with protect/leftovers/recover/rest/etc and getting around that bastard is less worth it than the Pelippers you're grinding levels off of of the coast somewhere.
Also, not only is it sporadically done, it's not particularly thorough about what it scales and adjusts.
Like, great, you beat beefed-up Team Aqua/Magma, Maxie and his level 98 creatures fall before you. Off to meet Primal Groudon. Surprise! it's half your level, at 45. You bag it with your level 90 Gliscor's False Swipe. You get to the eighth gym leader, and his very first pokemon is a level 100 Kyogre. Just drops that in your lap, 'ta-da.'
Oh, and if you were hoping to use traded pokemon or ones you'd ported in from another savefile, well, the badge requirements to have your pokemon obey you haven't been adjusted at all, so you gotta edit them again to have your ID or suffer as your fourth gym, bearing level 50 pokemon, gives you the badge to let level 40 pokemon obey you.
It's pretty good about making rare items, vitamins, and EV-boosting items readily accessible, but no similar effort was made for EV-removing berries, so I had no way to fix my team's EVs short of hoping the berry master gives me what I need one day or making adjustments in the save editor.
I'm trying to work out how to retool my team to get past the first trainer in victory road when they drop dragonite and lugia in double battle format in front of you. Perhaps my Weavile from my last romhack?