I don't see it as a "I had to suffer so everyone else should too" mentality. I see it in a "this DLCs were created by people and as long as the game isn't abandonware, royalties should still be given for the work put into it." Then personally, I never saw the experience I had playing with the older packs being bad. The base game alone was good. The expansion packs, also good. Maybe that was because back then bugs weren't so bad and the game was truly playable.
As it goes, EPs, I remain iffy on making free - make them cheaper by 50-60%? Sure. Game Packs, I'm not sure on whether cheaper or free. Packs with less content and less work put into them? Make those free. You'll have laundry, vacuums, hot tubs, popcorn machines, icecream machines, movies, rock climbing, butlers and so forth for free then. Make all the Stuff Packs and Kits free... but minus the ones that were completely created by CC creators or had a CC creator play an exceptional part in producing the items.
For certain things "missing" in the Base Game, I'd be more for a compromise. Give the Base Game actual seasons plus some extra decor that isn't provided via the free holiday pack or spooky stuff, but let the Seasons EP keep its own perks like the new plants, flower arranging, scouts, Father Winter, the Flower Bunny, holidays and the like.
Give the Base Game the jobs you can play via Get To Work, but have them be the usual rabbit hole like most jobs. You are still able to get the rewards that come with levelling up on the job. Maybe make the retail system Base Game. The pack meanwhile keeps the active jobs aspect, the worlds you go to world the jobs, Sixam, the collectibles, the aliens and the chances of being kidnapped by them.
Cats & Dogs... that is a toughie. Probably bring the ability to have cats and dogs in the game with the most basic of items they need: like the regular food bowls, the two most standard litter boxes, the lower end vacuum and only collars and sweaters. No paint customization in create a pet. You can take your pets to the vet via a rabbit hole. Cats & Dogs the EP, meanwhile... put all the stuff in My First Pets Stuff in it. Get the perk of being able to customize your pet with the color wheel and design tool. Have all the silly costumes in it. Give the some of the pet items a mesh refresh - beds that are not flat, cat trees that have an actual base that is not flat and gets hidden under rugs. It keeps the Veterinary career.