It's really incomprehensible that you've decided to repeatedly screw over the portion of your player base that actually spends money on the game and keeps you in business.
Wiping out everyone's DCs obviously had the worst impact on the people who spent a ton of money and crystals to get the competitive advantage that a fully developed DC stockpile brings. Conquest pass, the conquest calendar, the ascension pack, DC packs, crystals spent on refreshes & DC materials, etc...not to mention the time and personal energy invested by the players. So your initial mistake hurt this portion of the player base the most.
While rolling back the mistake you've made is clearly the only possible fix, WHY would you now choose to add on yet another unforced error by screwing over spenders AGAIN by giving everyone unlimited re-roll mats and thereby wipe out the advantage that spenders have ALREADY PAID FOR?!? Now a larger portion of the general player base can essentially build perfect DC's for free and eliminate the advantage spenders have purchased. While this is great for the f2p and light spenders, what the hell are spenders supposed to feel about this "make good" for us?
And to make matters worse, you've also decided to TRIPLY screw over spenders by eliminating the mats we would normally get when the DC set expires. The large number of DC mats and re-roll mats you get from an expiring set is a SIGNIFICANT advantage when building a brand new set. So now for the sake of the unlimited mats you're giving everyone, you're also penalizing the spenders yet again by eliminating the advantage we should've gotten when this set expires.
Again, all the above is something WE'VE ALREADY PAID FOR and you're eliminating it for no real reason and when nobody was really asking for anything other than a rollback and maybe some crystals for an apology. Honestly, why the hell should spenders like me continue to finance and support your incomprehensible decisions to screw us over?