J. Michael Straczynski credits Doc Smith as one of the inspirations for Babylon 5, you can see it in the Shadows vs. Vorlons conflict, including the use of and uplift of proxy races.
The Skylark series just isn't as good as the Lensman series, neither are his others (The Vortex Blaster and Spacehounds of IPC), but I did enjoy reading them.
For Smith fans, some other authors that have carried forward the tradition of space opera are:
Sharon Lee & Steve Miller - The Tomorrow Log, the Liaden universe books
Brian Daley - Terran Inheritance trilogy (Requiem for a Ruler of Worlds, etc)
James Schmitz - Telzey & Trigger stories (Baen reissue set is excellent)