Nolf: My arena decks usually fail too. I think the best I ever did was 17-6 and usually I'm out by the next day. But congrats on your success! (Even with mono fire, lol.)
After two days it's 19-2! Yeah! Sorry it's mono fire. I spent 4 points for upgraded cards, so one minor phoenix ("from Oracle") my only upgraded Fahrenheit, one Cremation and my only two (upgraded) shards (1 SoD, 1 SoG).
My whole elements story basically goes like this: I was given life cards and spent ages turning it into a decent AI3 grinder without even consulting the forum, of course lots of dragons and heals, only once I read the forums I realised there are better and faster ways. The little money I made I spent upgrading my druidic staff and Carapace. Without the Arena (and Grabbix) and Liquid Antimatter I'd still be there. The jump from Elder to Half-Blood is far too steep imho, I'm not sure I ever won a game. And T50 I also stood little chance against. I had to spend all the electrum I had to build Grabbix and Liquid Antimatter and for many elements I only have the cards I won in the meantime and I'm still missing plenty.
When the Arena was introduced (or rather, I took note of it) from all my AI3 grinding I was already level 25-ish. There, I had some decks that got into the top 20 - never spending points on upgraded cards cause I had so few, makes more sense to spend the points elsewhere, methinks. But that's not good enough for the gold league, plus even if the deck wins more games then it loses it can still drop out of the top 500 quickly. And now success, but it does feel a bit cheap, even I know by now that fire is rather overpowered. But apart from my original life it's the only element I actually know a little about.