Fire for 1R gave you the option to split the 2 damage between one or two creatures or players. Ice gave you the option to not only tap a target permanent for 1U, but also drew you a card.
Winterflame is definitely a powered down version of these two effects. It only allows you to tap creatures, which isn’t quite as useful as Ice, plus you don’t get the benefit of drawing a card. It’s much weaker than Electrolyze, which is basically Fire except that it also draws you a card, also for 1UR. It’s a weaker version of those two cards. Adding drawing a card as a third option while still only allowing two to be chosen would have made this much better. As it is, Winterflame probably wasn’t even good enough to be a rare.
Although Khans of Tarkir turned out to have plenty of powerful cards, Winterflame was certainly not one of them. It didn’t really see any sideboard play. Even in Commander, a format that tends to adopt many competitively shunned spells, only a handful of Melek, Izzet Paragon decks bothered to include this card. Outside of Khans of Tarkir Limited (drafts and sealed deck), this card was pretty much a dud.