The whole mini lacks contrast for a higher score.
The shading could do with being deeper on the face because it is too flat at the moment and really needs much stronger highlights, especially on the very top of the head. Some stubble on the head and jaw would look good too.
On the armour, the shading is good apart from the backpack. The zenithal light source you are using does not translate well onto the backpack, I suggest doing a top down light source. This will mean the shading will look uniform and match with the shading on the rest of the armour. The armour also needs more highlights on the backpack and the shoulderpad because the highlights on those areas do not match the intensity as on the leg with the damage. This is quite noticeable to someone looking at the mini because it is confusing as to why the highlgihts are stronger on the leg than on the top of the backpack and shoulderpad, it can make the mini look unfinished.
The gold needs more shading and highlighting. Look at people painting gold NMM and copy their technique, only with metallic paints. This makes the shading deep and matches with the light source affecting the entire mini\'s highlights and shades.
The white parts of the fists confuse me, they are the only part of the Marine\'s armour to have battle damage on them. I suggest either removing the damage and painting them like the U\'s (only with a tad more shade) or damaging all the armour so it ties in well.
I would suggest adding spot-colours to all the surfaces. Shade the blue armour with red and the red fists with purple or blue.
If you can, remove him from his base and re-attach it so his feet are flush with the object he is standing on, he is floating at the moment!
I hope these tips have helped! I think if you add some of these suggestions then you may get a higher score of a 7.8 or an 8
You could even look at the highest rated Sicarius mini\'s on the site to see how they have done it.
Cheers