Doom 2016's customization was actually decent. This will no doubt be a step up even with some silly aesthetic options added. The weapon customization is where it's really at though since it's what you see most of the time when playing.
A dying franchise? The series has been doing the best it has in a long time. Certainly better than how it fared in the Doom 3 era, although I liked Doom 3 for different reasons, but it wasn't the same run and gun experience.
The Doom 64 port getting a new episode is nice too, but campaign-wise they'll probably peak with Eternal. They took the reception and criticisms with Doom 2016's campaign and improved upon it here like tenfold.