@made_in_japan. I tend to agree with your arguement, though I would like to add a comment about eldar not being slanesh... well some think they are :) Also, I dont really like the face.
This is a very striking and colourful take on an eldar titan, but I think it suffers from a couple of things. One is that the painting needs to be much, much smoother. When you have a large area to work on such as this, you have plenty of space to smooth out blends. The other is that the overall colour choices dont harmonise with each other. I appreciate Harlequins are supposed to be striking, but there should also be a certain harmony of colour - they're not Slaaneshi, after all. So, overall it's a nice idea, but could be better executed.