Unless it's had an easy life I'd say they're broken in. And although this is an unpopular opinion, in my experience most speakers don't sound very different after break-in anyway.
T75's can be a fairly harsh speaker, so yeah trying some blends could work for you. Modern V30's aren't known for being smooth, but will make for an aggressive rock and metal cab. You could explore others if you're game - the Redback is worth looking at (X-pattern), or a pair of M Creambacks (up top). Both will smooth out the cab a bit, and make it more versatile.