Susanne is a bit of acquired taste. There are some people who LOVE the story and considere it the best and most mature Carla story and there are people who loathe it.
For what it's worth:
1.) She get a haircut later on
2.) I thought they had some very neat domestic scenes
Simply because it's not something you are used to see like that for women couples.
Even you decide not to watch the story, you HAVE to watch the scene where Carla goes a private strip tease for Susanne for some occasion (birthday? valentine's day? don't remember). Claudia Hiersche, hubba, hubba, hubba!!!!
Personally, I kinda always thought that especially early Susanne kinda reminded me of a cute self insert fanfic. Kinda representative for all the sweet middle aged housewives who watched VL and realized that they would go gay for Carla
But that's just my evil tongue talking.
Stella was controversial in her own way. It's one thing where you non German speakers are probably kinda blessed because the Stella actress was actually a model turned actress and she had A LOT of problems with clear diction. But since you don't understand her either it makes no difference to you
But yeah, because of this there were a lot of fans who didn't like the story because they felt she was one of the weaker actresses of the show. Plus, admittedly the story did kinda meander around. But I thought it still had its cute moments. But you kinda notice that it wasn't really a "main" story for the show. So Carla and Stella in the end got together a bit quickly and didn't really have those patented big languid soapy love scenes like you had in Canna and to some extent also in SuCa.