As someone who owned them for many years I can say that it's a headphone with 2 downfalls, one being in the sub bass as seen in any graph and the second being the infamous sennheiser veil and that is a dip in the treble. It's not a completely flat headphone, it's mid forward.

What you think of the headphone is music library dependant, if you want exciting then it is not the perfect headphone as its smooth treble isn't nearly as exciting as a metallic treble of a planar headphone, it's bass cant compete with a good closed backs bass.

It's a certain presentation, it's safe, it's sub-bass deficient with a slight bump in the mids and slight woolliness in the treble.

You most certainly can find headphones that prioritize exciting over being even, I highly recommend trying a denon d5200 if you're keen on using some eq.