This game needs a "Hero Agency" mode

Let's be honest the biggest problem with this game is that you really only use 1 unit. You pull one of the current best cards use that to farm a 99 luck unit and that's it. If you pull a stronger card that unit is gone never to be used again.

So I started thinking if you're not going to increase the number of cards you can use in mission why not send your spares off on timed (or controlled) missions of various difficulty where the cards stats get counted to give you a probability of success and then gets put on a cool down afterwards (Maybe you can't use it in your main missions to put you off from using your strongest card if you have an event to farm). A few other games have this feature (I think one of the top down Marvel games does), the missions could give you a new currency that you use in a shop to buy items, gadgets and new units. This would create a lot of incentive to farm more cards and give your gacha 5*s who aren't good enough to cut it a place where they can still be useful

Just an idea I had to add something to the game that won't completely change it and still fits with the source material