It's kind of annoying having skins you already own changed so drastically, especially since we aren't offered refunds when they are.
The old Traditional Sejuani had some really nice things going for it, for one, looking at just the face, it was easy to tell, THAT IS A GIRL. Sejuani skins haven't always been the most telling (aside from giant boobs) and with the current default splash I've met several people who think Sejuani is a male because of it (less so in S7 and more in S3, 4 and maybe 5) So the fact that the one skin that made it so obvious she was female now looks more manly than the others is kind of annoying.
I'm not a big fan of helmets but she used to have her hair coming out of the broken horn on her helmet, that was super cute. I think it'd be really great if we could keep that hairstyle just unhelmed. I had a hard time finding an exact copy of it, but something like this http://www.polyvore.com/cgi/img-thing?.out=jpg&size=l&tid=28395994 A side ways pony tail coming out, being really fluffy.
The other big thing is her face, in the original splash, she's really pretty, but it doesn't take away from her being tough, she doesn't necessarily look approachable but it's not in an ugly way. Where as this new one I'm kind of surprised she doesn't have a cigar as well. She doesn't necessarily have a mean face but the scar really doesn't look good at all and combine with the hair it just doesn't look good in my opinion.
I've always hated how some changes end up being the complete opposite of what they started as yet there are never refunds for it, like how Sion used to be a lifestealing sustain king, and now he doesn't have any sustain at all. You can argue that the change made the champion better in many ways but it was still a loss of one thing in return of the opposite. Aside from the AP Sion players most Sion players back then probably wanted a life steal god more than a tank. He's not the only one either, Skarner a duelist that now has low duel potential, or MF a champion that used to be about hitting the same target over and over now gets punished harshly for doing that and instead is encouraged to swap between two targets despite being such low range.
I get that when you buy a skin or champion it may be changed, that's fair, champions get too OP they need nerfs, if they suck you gotta buff em, all that's fine, some mechanics just don't work and need to be removed again it's fine, but when the changes are so opposite of what it was it just really feels awful. Like I own this feminine Sejuani skin and now I'm gonna own this manly Sejuani skin. If I wanted Manliness though I'd just use one of the others.