As mentioned previously, the modding scene for SSE is healthy and active and many great mods have been created or ported over.
However, the catalyst for true parity with OldRim will be the release of SKSE64 which is TENTATIVELY due to release in beta form this March according to the devs.
For those who don't know, SKSE, or Skyrim Script Extender enables a cornucopia of the most popular mods of old by allowing the use of custom scripting etc. these mods include SkyUI, the complete version of Frostfall and Campfire, Convenient Horses and many, many more.
Another key feature of SKSE is the implementation of the MCM, an in-game mod management menu that is a godsend for anyone running a heavily modded build.
Hope that clarifies things! Cheers.