Arena is basically one of those things where you're either getting the medals easily, or it's a terrible chore.
I'm able to remain in the 3200+ range, and so I very often get refreshes with teams that are basically just single arbiter/etc... IE easy wins. I also very often get teams that are the standard OTK kit (Warmaiden/Kael/etc...), and against those I can very easily win by just putting a full DEF team in.
If you're having trouble climbing arena ranks, I'd suggest you focus efforts on one of two things:
1) Get your own OTK team. A cookie-cutter one would be Khatun lead, with Warmaiden/Spirithost/Kael as your remainder. Put Khatun in full speed gear - you want her to be at least 250, ideally higher. Put speed and acc gear on Warmaiden, and speed gear on Spirithost. Kael does need to be speedy as well, but he doesn't need to be quite as high. Then just find teams which don't have a speed lead champ, and you should be able to climb.
2) Get your own full DEF team. This one's a bit harder to cookie-cutter, since out of the box you don't get much for free. If you've played enough to have Ghrush, he works well. Ditto for Rhazin if you've got him. Other good candidates are Sepulcher Sentinel, Skullcrusher, Brago, Ignatius - really any DEF champ with good abilities. Gear them up with DEF and RES gear. Your plan is basically to resist the debuffs from Warmaiden/etc, and survive the nuke from Kael/etc.