Spoiler
Snow'El #2- Beautiful bright indigo is so striking against her white coat! Her angel symbol is very unique, and she's a pegasus! I just love her little halo! The other two in this set were pretty boring, but they went all out on her for some reason. I look for her occasionally, but she's so expensive! I'd die if I thrifted her!
'08 Minty- My favorite childhood pony gets an amazing makeover! Mint green is my favorite color and pairs so nicely with pink. The designs just add to the lovely gradient down her legs! The Core 7 pose looks so amazing with the head-down-head (why couldn't they have used it more often?) and her hair colors make her stand out against other Minties. Perhaps my favorite feature is the snowflake over her eye- reminds me of Dream Gazer! The only downside I can really see is that she didn't come with any winter gear, but she would look crowded with it. As-is, she's perfect.
Chilly Breezes- Her color scheme is so pretty. If you don't have any ponies with that pastel teal hair color (assuming it's the same color on Bashful Bonnet), you're missing out. It's so much prettier in person and has a unique shine! Her accessories are cute enough, but not my favorite; still, her colors are enough to get her high on this list.
Velvet Bow- This pose is one of my favorites! It's not quite as cute as Crystal Lace's, but it's just so cute to have a pony looking up at you! Did I mention her color scheme? That grayish periwinkle makes her stand out and her hair colors are amazing along with her symbol design; I especially like her dark eyes. Her accessories are unique; not my favorite of the group, but they are very fuzzy and cute!
Marshmellow Coco- Despite the odd spelling, her name is cute. Her eyes are striking, and her symbol is just so warm and yummy! I'm among the seven people who actually like her pose, so that's a plus for me, too! Accessories are nice; that fuzzy tail bow is to die for!
Sno-Glo- I can't give you a concrete reason that she's so high on my list. Everything about her is just kind of... meh, at least on its own. But all together, it just... does it for me (whatever "it" is!), so here she stays!
Winter Wish- Cute name, cute accessories... and cute eye color that stands out against her pink-on-pink. The aqua sort of echoes the green in her symbol, and with the yellow, it sort of echoes the iridescence of the tinsel in her hair. Simple, but beautifully so.
Snow'el #1- Alright, I just like her colors and pose. That's it, simple as that. Cute accessories as well, but that's standard with these guys.
'05 Minty- One of the many variants of Minty I, she's a bit brighter and cooler in color than her perpetually-screaming peers. I'll admit that nostalgia pushed her this high; my childhood Minty is a bonus pack Minty I with a properly printed hoof heart! The pink in her symbol kind of bugs me, since mine had red, but she's not bad at all. Her scarf and socks have an adorable pastel striped pattern that make them my favorite winter pony accessories! She'd be higher if I'd based this list more heavily on accessories, but pony design comes first to me, and she's not too unique.
Candy Cane- Striking colors, if not overly unique, but her hat is fluffy and cute. The donkey pose was one of my favorites as a kid, since it was Minty's pose and all the ponies in it just look like they're screaming with pure, unfiltered childhood joy! I get nostalgic for running around and screeching without worrying what others might think of me- that's the best part of childhood, and, if nothing else, we should teach our children to enjoy it! My parents were so very patient with me!
Mistletoe- Just a solid design, that's all. Fun Fact: Hasbro trademarked the name "Whistle Toe," but never used it. Could it have been an early name for her? It just sounds strange!
Jolly Lolly- I put her above Mittens #1 because I like the turning-head version of Wysteria's pose more than the static-head version of Sparkleworks' pose.
Mittens #1- Different order of hair colors, but basically the same pony. I also like Jolly Lolly's name better.
Pinkie Pie- Yawn. She gets points for using a different Core 7 head, though; it gives variety where it's desperately needed, but she's still another Pinkie Pie.
Mittens #2- I can't decide if this is the least accurate rerelease of a character or the laziest way to design a new one! She's prettier than the spot on this list may suggest, but it's hard to see her as anything other than an inferior version of Snow'el #1. I just don't like the purple as much as the pink.
Toboggan- Her colors are nice enough, but she doesn't really stand out to me without her accessories. Her hat is absolutely ridiculous in the best way possible and is really the only thing that gives her an identity. Her name conjures up memories of my transition from a northern state to the south when my family moved when I was young. Is her name to-BOG-gan, a sled, or TO-bog-gan, what southerners call a winter hat? She keeps me up at night, so I docked points for that. I'll have nightmares tonight of me being the new kid and being utterly confused when others were just trying to compliment my choice in headwear...
Snowflake- I don't dislike her, but for some reason, her color scheme and symbol aren't that special to me. There are monochrome ponies higher on this list, but... I guess blue's just not my favorite color? She's still cute, though!
And now, last, and by far least...
Rainbow Dash- The only new thing she brings to the table is probably the least adorable scarf on this list (though it is still cute). I'm fine with the Core ponies, but you really only need one of each variant. Winter Pinkie Pie had a different head, Easter Toola-Roola had a gradient leg, Easter Cheerilee had the superior different head, Halloween StarSong was the only one without glitter or tinsel, V-day Pinkie and Sweetie (both years) were amazing... This is just a Rainbow Dash. There's quite a bit of a chasm between her and Snowflake; this one is the only pony on this list I wouldn't miss if she were announced but never released. Perhaps that's a bit harsh, but all the others are unique and she just isn't.