It is worth remembering that this game is nearly ten years old. When you consider some of the clothes you were wearing ten or even twenty years ago I doubt very much they would hold as much appeal as they did when you purchased them. The same goes for base game clothes. However ten years ago it was all new and reasonably fashionable. The biggest selling point of all was CASt so you were not restricted to a limited palette and you could give your sim a very individual look. Personally I went several years with only one expansion and a couple of stuff packs. Apart from the base game I had a couple of store clothes and hairs but I didn't feel my sims were missing out or were unattractive to look at.
Some of the base game hairs are pretty lame but there are a number of classics, like the French Pleat and the Bob. These never really go out of fashion and, as others have said, with CASt it is possible to create attractive vanilla sims.
https://i.imgur.com/AB0JqpT.png
This is Baby Doll. Her French Pleat is base game and I have customised it using CASt. Her dress is one of the first items I bought from the store.