OT: another Bosch?

"I tend to like mysteries, some suspense, likeable protagonist, and preferably not too dark."

That seems a pretty fair approach. For me, a likeable protagonist is important. Who wants to spend 500 pages with a protagonist who is a complete arse?

Besides that, I just want a well-told story by someone who can clearly demonstrate that they know their subject. I don't mind if it gets a bit dark, just so long as it remains reasonably realistic.

If you like espionage, I highly recommend the QUILLER series by Adam Hall. It's written in the first-person and you only ever get vague glimpses of the "big picture". Mystery and suspense are both frequent and important parts of these stories and I personally find the protagonist quite likable.

ant-mac

I was going to suggest Robert Crais. His work is somewhat similar to Connelly in locale (LA), subject matter, tone, and quality. Scott James and Maggie are major supporting characters in The Promise, Crais' most recent novel featuring his most prominent characters PI Elvis Cole and his silent partner Joe Pike, ex-military, ex-mercenary, ex-LA cop. Pike is sort of a (much) better written, more realistic Jack Reacher (with a permanent home). I've read this and Suspect recently, though in reverse order.

I'd also recommend that you try Raymond Chandler, who wrote seven Philip Marlowe novels between the late '30s and late '50s. They're PI novels, not procedurals, but this greatest of all noir novelists is the single clearest Connelly influence. All the novels are good, but the best are The Big Sleep, Farewell, My Lovely, and The Long Goodbye. The first two were made into classic noir films that I'd also recommend: the 1946 version of The Big Sleep with Humphrey Bogart as Marlowe (not the '70s version with Robert Mitchum), and the 1945 Murder, My Sweet (Farewell, My Lovely retitled) with Dick Powell as Marlowe. (The Long Goodbye was also filmed by Robert Altman in the early '70s with Elliot Gould as Marlowe, but it is a controversial film that is decidedly not in the noir tradition.)

An interesting note: Chandler is an obvious influence on many crime novelists, including Robert Parker. At his death in 1959, Chandler left the opening chapters of a last, unfinished Philip Marlowe novel that was completed and published in the late '80s by Parker as Poodle Springs. I've enjoyed Parker's work for decades (and am still enjoying the posthumous Spenser novels by Ace Atkins, which are virtually identical in style and quality), but he's no Chandler as Poodle Springs clearly demonstrates.