I always though treasure cards wer no were close to fair in pvp matches. I'm so sick of losing to people who are a lower level than me. I think we shouldn't be able to use treasure cards in pvp.
I would have to disagree with removing TC from PVP. It can be very annoying, but for low level PVP, using TC is a very good strategy. To have a better chance of winning, you should farm for the best gear used at your level. It can be different for PVP players though. Most PVP players use gear which is bought by Arena Tickets.
Save up on Arena Tickets and do Tourneys. Tourneys give a good amount of Arena Tickets even if you come at a low place. Once you have enough you can buy the gear from the vendors in Unicorn Way. Or, like I said farm for good gear at your level, it's all up to you which route you want to go.
Having a good pet helps A LOT in PVP. You could go for an all out resist pet, damage pet and even an in-between pet which has a good amount of resist and damage. It's all up to you. Find someone who is willing to hatch with you multiple times until you get a pet you're satisfied with.
Oh, and also for gear which can be bought for Arena Tickets, you might need a certain PVP rank.
Level limiting treasure cards would help immensely with this. If a spell is not given until level 48 for example, a person would need to be at least level 48 to use that TC.