There would still be reasons to get play Crota's End even if the VoG weapons were upgraded to the current damage cap. The new raid weapons have uses and are good for different situations (and IMO are better then the VoG weapons in terms of perks), and playing the raid is the only way to reach the lvl cap. You can also get unique emblems, shaders, ships, and it's also the only way to upgrade the Husk of the Pit all the way to its exotic version. It is also the only way to get a couple of grimoire cards, for those who care about them. I see plenty of reasons to play. If Bungie is truly concerned about people not playing a new raid because the old raid weapons do the same amount of damage then they could make it so that the only way to upgrade old raid weapons is to get materials in the new raid. Easy fix.