Linux Mint 5 Elyssa will come with new themes. Here are two of the themes which will be included: WildMint and Lightning.
There are no plans to change the default theme so far so it should look exactly like in Daryna (It was renamed LM4 in the theme manager). If you’re into artwork you probably noticed these two themes are using Aurora (the engine used in the latest Fedora release). We’ll also have a bit of Murrine and a few extra engines available from the customization tab.