The latest 3 stuff packs were really good (especially Paranormal) so I'd be sad to see them gone after seeing their true potential. If SPs started with the same quality they would have been much more appreciated from the get-go.
Honestly my biggest gripe with kits is the lack of new hairstyles, I liked that they added 3 more to the base game with the release of Incheon Arrivals and Fashion Street but they haven't done much of that since (just randomly releasing a single hairstyle in a patch or making some pack ones base game). SPs add new hairstyles as well as new clothing and stuff so I appreciate them more for that alone. :P