It's not entirely un-true. Cryoburn is another Lord Auditor Miles Vorkosigan investigation, but in the end it rather reinforces the "promoted to an awkwardly high level for a protagonist" aspect; the other two that have come out since then feature other characters, with Miles appearing as a supporting character if at all. Captain Vorpatril's Alliance is a Miles-less adventure for Cousin Ivan, and Gentleman Jole and the Red Queen features Cordelia. (In some ways it's a book-end to Shards of Honor; whether that means it's the end of the series, only time will tell.)