That's not to say that they're bad (though at least one is objectively bad). Just old and male.
Here's three for diversity:
- Lois McMaster Bujold's Vorkosigan Saga. Character-driven space opera, with side-trips into mystery, thriller, and (gasp) romance. Start with the short story collection _Borders of Infinity_ to get a taste for it.
- Elizabeth Bear -- lots of variety, but _Carnival_ and _Dust_ are excellent. Respectively, they are an espionage/police procedural and a political thriller on a doomed starship.
- Linda Nagata -- she's best known for the epic nanotech series (The Bohr-Maker, Limit of Vision, Tech Heaven...) but recently started a near-future series about the impact of cybernetics, prosthetics and early AI (First Light).