Echo shard in my personal opinion is really not healthy for the game and in practice feels like a street brawl item that somehow sneaked over to the main game. Sure it's a t4 item that isn't mandatory on the majority of the cast but I think it encourages a lot of "cheeseing" and is generally unfun to play against for enemy. For reference I play Doorman, Sinclair, and Paradox and I know from first hand that all 3 of these characters benefit a lot from echo shard (with double cart stun, Double bunny and Double Nade) and it also benefits abilities like Haze Knife, Mirage Tornado and Ivy Stone form.
All of the characters I've listed before have abilities that provide heavy CC/stuns which isn't all that bad considering they usually require a "skill shot" or at least some planning to land. The problem comes once you land prior ability you are guaranteed to land it once again. For example, the first haze knife, Sinclair Bunny, Doorman Cart isn't all that bad but when you get incapacitated by said ability there is nothing you can do to stop the enemy from landing it once again and in effect echo shard results in all the stun abilities lasting twice as long with little counterplay for the opponent (besides a teammate rescuing beaming said victim out). You can make the argument by spending 6.4 K on an active slot item you lose out on other upgrades that could've given you more damage/survivability but is that really so bad when you have an ability if you land it once and can coordinate with your team pretty much guarantees an instant kill on the enemy?
I feel theres a couple of ways you can rework this item without just removing it from the game such as increasing the cooldown even further (e.g. 35 sec -> 60 sec) but that still doesn't solve the fact that it sets up a prolonged stun on your enemy, which doesn't solve my personal gripe with the item. You can also give it a damage penalty like curse or even some other draw backs in stats (Like weighted shots decreasing your stamina/dash movement).
My proposal is to make Echo Shard an ability that can imbue a charge onto nonchargeable abilities and have the cooldown between charges not be instantaneous (e.g. Holliday Barrel Charge taking 7 seconds to refresh before Max T5). This would make it so that if you are caught by an Ivy Stone Form or Mirage Tornado you aren't immediately stunned twice as long and have some time to run away. To compensate, we can have this new echo shard upgrade from Rapid Recharge and have it the option to give additional charges (and maybe shorter CD between charges but that might make abilities like Shiv Knife and Holliday Barrel a little disgusting).
I think Echo shard can be reworked but idk maybe it should be removed from the game and become a street brawl exclusive? let me know your thoughts
Edit: My idea to have Echo shard upgrade from Rapid was so that the noncharged ability having an extra charge will only ever have 2 (at reasonable CD from each other) and you wouldn't run into the problem of having Abrams have 4 wall charges. Sorry if that wasn't made clear!
Let me know what you guys think!
P.S sorry if the formatting and writing is bad, these are some late night thoughts.