I'm fine with this. It think they have a brand here either way. I'm reminded of The Dark Knight. It was every bit the Batman brand, but it didn't include the word Batman. I think that sort of titling is in now, and it has a sort of underline simplicity to it all.
And it's not as if the Tomb Raider brand won't still be usable. They could easily do both. Have a Lara Croft game on consoles and a Tomb Raider game on the PSP, for example. Again, I'm reminded of Batman, or more specifically, comics in general. How you can have multiple comic series out about the same character at the same time, all with various titles and subtitles (Batman, Detective Comics, Batman & Robin, Batman: Legends of the Dark Knight, etc).
I think the same branding tactic could be applied here, if they so choose.