Lads, seriously with all this "my character will be unbalanced!" do you realise, if you don't assign focus points to the weapon skill it will only advance with 0.05% eventually and wont really progress above like 75? And why the **** do you care how others want to enjoy their game? Gaining xp in the arena will only affect your game if you use it, but if you say training in the arena is not a real combat and unrealistic, then you are dumber then I originally thought. Many people wrote down examples already, so here is another one maybe it will go through this time: back in medieval times lords and their men-at-arms rarely fought in any "real" combat (unless their whole country was at war, but thats another issue), in the majority of their time, they were fighting in the training fields with wooden swords or totally dulled and pointed practise blades, because guess what, there was no "wounded/recovery system" in real life (if you got injured, you had a fair chace of dieing, unless it was a minor scratch only) and guess what they didn't want to die. And guess why the tournaments were so popular back in time? Yeah, they had no other opportunity to fight other previously unknown knights and experienced soldiers and learn some valueable experience on the top of practiseing their asses off in the training fields. So let's turn this thing around: both realistically and RP-wise it is more than perfect to be able to hone your skills in the game.
If you are afraid of unbalancing your character, well then you should consider improving your self-control. If you want to RP that your character progresses slowly, through multiple days? Then simply play 3 rounds per day. If you are unable to do that, then you should see a therapist. But if you want to lvl up your skills to like 75 in an hour then never set foot in the arena again, then you should be able to. In single player the more possibilities the player has the better. This is not multiplayer, it does not affect you, unless you are unable to control yourself and the flow of the game. So please pull your nose out of other people' business and dont try to limit their freedom by stamina/no-xp-arena or whatever. If you cannot enjoy the game when a feature is enabled then you are the only one responsible for that. TW should turn their eyes to much more important issues. Arena is fine as it is, and offers a sufficient freedom in it's current state. Deal with it.