For the first time ever, we're getting an alternative to the Arena. For a price, players can put their skills to the test and be rewarded based on the results. I think this is a very good thing overall as some people may tend to be better suited for one playstyle over the other. But the interesting thing is, alongside this arena alternative, we're getting a casual version of it that will allow all players to just goof around with the game mode at no risk, just for fun! IMO, this is awesome. But then I realized, if Duels can have both a mode where you can test your skills and win prizes for a small cost as well as a casual variant, why shouldn't Arena do the same?
It seems like it'd be ridiculously easy to implement and would be extremely fun. I mean, if you like playing arena that is, then it'd be fun. All the work's been done, the system already exists! They just need to make a few tweaks to adapt it for a casual variant.
The way I envision this being implemented is that it would function virtually identically to paid arena runs. You pick your class, you draft your deck and off you go! (duh, right?) However, there's also room for Blizzard to profit from such a mode as well. Imagine that for everybody, you have restricted access to just 2 random classes every time you start a casual run, as opposed to the normal 3 options players currently enjoy with paid arena. Then just make it so players have the option to pay (with either actual money or gold) to unlock the 3rd option. Exactly how the current "Perks" system works in Battlegrounds.
It would also work on a ranking system similar to how duels and battlegrounds are ranked. This would incentivize players to do their best instead of simply abandoning a casual run repeatedly until they get one of their preferred classes or solid draft picks. I mean, they still could, just like a Battlegrounds player can repeatedly auto-concede until they got a favored hero, but it would tank their ranking.
There's even more opportunity here though. With casual arenas, you can now have daily quests associated with arena runs. Or the new weekly quests. Or achievements for that matter. IE: Reach 12 wins! With the upcoming Progression and Reward overhaul on the horizon, this seems like an obvious, logical step.
It's clear that Blizzard wants to implement new game modes to bring in new players, bring back old veterans, and keep people invested in the game. And arena is just sitting there, ripe and ready to be molded into the next, great, casual game mode. Like I said, all the work has already been done and ready to go. So I ask, why not?