If you're willing to invest the extra sp you can use 2 imbues because there are advantages to them all. Ice can slow down mobs or enemies in pvp and freeze them so that they take longer to hit you. Lightning imbue has splash damage so if you need to agro mobs it helps alot, also gives a status that reduces parry ratio (or is it dodging lol i get them confused all the time!) And of course fire has the most damage and continues to give damage when the opponent gets the burn status.
It all really depends on your grinding style. Since I'm pure INT i use fire, only because fire is my main mastery for the nukes but since I'll be farming for ice soon I plan on adding the ice imbue so that when I get in a tough situation, multiple mobs, giants etc., I can use the ice to slow them down. It's really good for pvp unless your opponent is immune... lol.
But try grinding and pvp'ing with all the imbues and find the one that works best for you.
You could always de-lvl with cursed hearts quest or just keep them at lvl 1 until you've decided. Good luck
