Let me start this off by saying the art itself (shading, etc) are all very well done. That being said, I feel that the design for Tryn's outfit was uninspired and brought no original elements to the table other than the sword itself... It simply felt like an exact duplication of the Ashe skin, only gender swapped. I feel you took the safe route with this and missed an opportunity to really flex your artistic muscles.
I love Taric in this, he seems so engrossed in the whole process, lol.
I see your point, and it is valid in the case of the single shoulder without armor (that is one of his trademarks, afterall), but I will have to disagree with you on the other points (in my humble opinion). The full pants are simply extensions of the black leggings ashe is already wearing, the chestplate is an extension of her bra-like chest piece, simplified by 1 row of armor, and the gem located in the same spot were you to grab her brassiere and tug it up and flat. The only real different with that (other than the fact it covers more skin, and the removal of 1 row as I mentioned before) is that the scaling is reversed in it's arc. That is not to say there are not small items that are different, but as I (believe) I argued previously, it is changes to address a gender swap. (Crown instead of tiara, chest pieces instead of battle-bra, pants instead of leggings, etc). The only truly unique pieces I noticed where I feel the artist shined and executed their own creative license would be his sword, the removal of one shoulder guard (as you brought to my attention), and the crown (though it does still feel like a gender swap, but admittedly, not a straight swap; To choose to depict it that way was completely on the artist, and I applaud it.)
This next paragraph is only based off what I've seen from the other picture linked, so excuse some of my ignorance, I do not play tryndamere and am not familiar with is demon armor set (though I did look up a few screenshots and the splash art to make sure). Based on a glance, once more the artist has given themselves much more liberties with this piece to try and give ashe more of a unique identity. She has horns, her eyes bleeding downwards with ice blue and not the more harlequin style makeup tryn is sporting, the tiara (made of leather it would seem), giving her the signature hood (unnneccessary since she has skins without it) all the way to the frayed and colored cloak. Once more the artist has seized the opportunity and given us a unique weapon for ashe. Even her boots are not mirrors of tryn, but instead reference the style of them but made her own with the leg armor, the lack of ankle cover, and the leggings beneath. Her shoulder guard is bejeweled with what could be interpreted as demon eyes but still refers to the spikes of the original skin's design, and there seems to be an additional guard slightly hidden on the opposing arm. Infact, the only parts that -are- exact duplications (unlike the amethyst skin) is the skirt (shortened for the gender swap) the coils embracing her, the belt (from what I can see), and the wrapping of her left wrist/forearm.