Rogue Core presents an opportunity that I firmly believe they're fumbling.
Allow me to tell you about the Chaos Wastes in Vermintide 2. For anyone unaware, Vermintide is a L4D style co op shooter with hero units that all have their own loadouts and skill trees. The core game is exactly as you'd expect but the dev, Fatshark, has an unhealthy fixation for tacking on alternate game modes that the small but dedicated community has been resoundingly against. Their first foray into this nearly killed the game but their second attempt, The Chaos Wastes turned out sort of ok. The Chaos Wastes is a roguelite mode where you select your character and keep your skills but gain new ones, both ones exclusive to the mode and ones that you'd have otherwise been locked out of from the skill tree. Weapons also had new abilities. This was all well and good but despite theoretically having more replayability than the base game, it died out rather quickly. There is probably a myriad of reasons for that but I believe that it was mostly due to it not being the type of content that the community wanted. However, people really liked two things from the Chaos Wastes; they liked the skill boons and weapon traits, and they liked the map mutators. Map mutators made it into Darktide which have definitely paid off, but all of the skill boons and neat new weapon traits remained in the Chaos Wastes, their potential never realized. Adding even just the weapon traits could have spiced up the base game in incredible ways. However, that would come at the expense of the DoA mode that FS worked hard on shoving down players' throats so obviously that never came to pass. It exists on modded clients though and that's where all the good players are now anyway.
Right now, FS is in the process of adding yet another DoA mode in the form of L4D style versus. Excellent use of time.
Why bring all of that up? Because Rogue Core sits in the same position as the Chaos Wastes, except GSG is expecting players to fork over cash cash money. Rogue Core will likely introduce elements that would be right at home in the base game but for Reasons™ they won't be. And if they cave and do, it invalidates the entire purpose of Rogue Core existing. It should have been a mode to introduce wacky ideas as A/V testing and gradually take the best of them for the base game. Shit, I think the base game could do with more roguelike elements. GSG will probably come out ahead by double dipping into existing players' wallets but fracturing the playerbase is another mark in favor of DRG's decline.