I'm going to answer my own question, is the AKG K702 a better option compared to the Philips Fidelio X2hr in terms of sound quality, sound stage and instrument separation, in a word, yes.
AKG K702 = a proper open back, sounds absolutely amazing straight out the box, perhaps a shade lacking in volume level due to the 200mW drivers, the sub bass interferes with the vocals, backing the volume off a little solves that. For the price I'm well happy for the sound quality I'm getting.
The X2HR can feel a bit grainy sometimes, but I have the HD800S and I often prefer the X2HR to them. It's not as technically accomplished, but it gets many many things right.
When I first had them I wasn't impressed, but their tuning has grown a lot on me.
The X2 sounds too dull and boring to me after having tried different cans. Bass and soundstage is alright, but it sucked away the mids and sparkles so much that it didnt impress me at all. One of the most comfortable headphones for its size though, that made it worthwhile in my books.
Its sibling, L2 though, is literally hot garbage. I was unaware till at some points that its treble was making my ears bleed. All in all, very disappointed going for the Philips lineup