According to Kotaku's sources id Software are facing serious difficulties in developing Doom 4 with at least one major reboot taking place in the last five year while Rage 2 has reportedly been scraped altogether.
A statement from Bethesda marketing head Pete Hines said "An earlier version of Doom 4 did not exhibit the quality and excitement that id and Bethesda intend to deliver and that Doom fans worldwide expect.
"As a result, id refocused its efforts on a new version of Doom 4 that promises to meet the very high expectation everyone has for this gameand this franchise. When we're ready to talk about the Doom 4 id is making, we will let folks know."
According to Kotaku's piece when Doom 4 was originally planned it was intended as a "rework" of Doom 2. This would carry on with the studio's tradition when developing the series with Doom 3 being a re-imagining of the original Doom.
Apparantly players were put in the shoes of a normal human who was gradually tasked with joining the Resistance, the group of civilians and soldiers formed to take on the demons invading Earth.
Kotaku's source said "People referenced Call of Duty. There were jokes like, 'Oh. it's Call of Doom.' They referenced it because of the amount it was scripted – there were a lot of scripted set pieces. There was kind of recognition that in order to be a big shooter these days, you have to have some amount of the big, bombastic movie experience that people get pulled through."
Another source commented "The coolest part… were the horror and shock elements, unfortunately be somewhat pointless and contrieved shooting galleries of hoardes of uninteresting enemies."
As development on Doom 4 faltered Bethesda reportedly became more involved in overseeing id and cancelled Rage 2 while downsizing the original game's DLC plans.