So as a very much non-whale, I have mostly ignored the "top 6 buyers get to design a summoner" bit, as it is irrelevant to me.
Or so I thought. I was thinking about this today, and it seems like it'll be ripe for insider trading.
Imagine the following scenario. Someone is designing the fire legendary, and is sitting on a hoard of venari heatsmiths they picked up for a few DEC each. They are going to design a fire legendary which gives everyone thorns + return fire, which will make the heatsmith go from a loser to a winner overnight. In preparation for this, they tell their guild about it, and everyone buys up the stock of venari heatsmiths. The next day, the legendary is revealed, and there are no heatsmiths to be found, except those owned by the guild which is now gouging the price. (I know this isn't the best example, as everyone probably has a lot of heatsmiths, but it has the simplest "this ability is useless now but with the right summoner would be amazing")
Is there any mechanism in place to prevent that? If it's one of the top 6 CL buyers, it's basically guaranteed to be a whale who can do this kind of market manipulation even without having insider info.
My solution would be a "designer diaries" or something. Posts by the devs detailing the design process over the whole course of it so people can see where the legendaries are heading and can speculate accordingly. The top 6 can still share info as to what they'd like the legendary to be before anything is posted, but it won't be sharing any concrete info as the card's deisgn will still be in flux.