You want more than 8 bits pre-color IN the panel (and video card) if your goal is a full, high-bit display path, which is useful if you want to see data that has no banding without banding from the display path. Ignore Eizo (and others) suggesting higher than 10-bit is in some way 'better'. The key is more than 8 bits per color in the entire display path and data.
2K, 4K, less important IMHO (you want to see tiny, chicklet-sized UI on a 27", then you'll love 4K. I'd hate it).