Since there’s only a select number of heroes with available red skills, I’d like to petition that they be re-introduced to the many shops.
For some, the extra chips have been sunk into upgrading mods, because that’s the direction the game headed for spending surplus. Now there’s a massive requirement of these chips to unlock a new skill, with few resources to gain said chips.
For myself, it’s Zurg. I spent a lot of hero chips to get all his mods to a high upgrade level, and now have 5 Zurg chips. Suddenly I need 200, with no reliable source of attaining them. Yes I could raid elites and reset and make no progress on anything else. Yes I could open thousands of diamond chests and maybe get a handful (the pool is too big now).
But the ability to buy 5 at a time from a shop? That’s a solid, proven method. Shop currency tends to stack up due to the minimal changes in availability, and this would likely give people a reason to start spending.