Monica Rathbun points out some of the trace flags which are no longer important in SQL Server:
If you have ever attended one of my performance tuning sessions, you know I tend to talk about trace flags. Trace Flags can help fix performance issues and some are now defaulted in later SQL Server versions. In my opinion, when a trace flag’s behavior defaulted in a version, then you should potentially put them in place within environments that do not have them implemented. Below, are a few of these particular traces flag along with Microsoft’s definition of what each trace flag does, taken straight from MS documents. I have also included a brief commentary on each one. As with any change, you should be sure to thoroughly test before implementing these trace flags into any production environment.
Read the whole thing, especially because at least one of them is still optional and defaulted to off (but able to change at a different scope).