Chiming in as one of the other leaders of Sponge, I've always believed that making heavy modifications to the game (as coremods sometimes do) would benefit from being viewed source, since often times debugging odd interactions between SpongeForge (and SpongeCommon as the larger part) have been often times difficult to say the least to work out where the issue lies. That being said, I strongly support the idea around coremods being viewed source for the sake of inter-coremod compatibility overall, as the goal with SpongeForge has always been about remaining compatible with as many mods as possible out of the box (even if the technological attempts at maintaining that compatibility is not as evident or thought up very fast). As @Zidane has mentioned, SpongeForge will be making the necessary changes in the very near future to abide by these requirements. As per usual, my goal with inter-mod compatibility is always to provide as much descriptive console spam error logs to help Sponge and/or the mod itself get a better fix and make the users happier overall.