While there are various reasons for many new or returning, it's odd that it's happening mostly in the same time frame with no ads at all. It's selling itself.
What ever the trigger is, it's welcome. IMO, The more older names appear, the more likely some want back in too. The more people playing = more people wanting to play.
Despite the fact that the WWII genre of players seems to be tapering off, the game can still pop a little more.