TBH the absolute best option in the long run would be to remove chests completely. Because there are a few good items in the chests, OTM has to pack them full of junk to make them less common. If chests were 100% removed, that would fix a majority of the plat concerns imo. Need hastest? Buy em from store.
Follow up with that, get rid of heroic elixirs, or else put all heroic versions in the normal store to be purchased for more than normal supers.
There's so many complaints and conspiracy theories from people who don't understand gambling, plus server economies would finally calm down.
Or at least remove all elixirs and restos and idols from chests. Leave chests with only fashion and aeon stuff. (Adding all heroic stuff in stores).
That sounds like a nightmare, idols, restos, everything would be extremely expensive, imagine what this would do to server economies, not to mention how many players would probably quit as not everyone buys enough platinum on a regular basis to play eg normally like now.