Hi Benny,
1. You write "So the latest NWDS would still be in action" for 7.4. On SAP Support Portal, Software Downloads, Installation 7.4, Clients, NetWeaver Developer Studio, this reads like this:
"As of SAP NetWeaver 7.4, SAP NetWeaver Developer Studio is no longer available.
If you want to use SAP NetWeaver Developer Studio with SAP Netweaver 7.4, you can still use SAP NetWeaver Developer Studio 7.3 including enhancement package 1. For more information, see SAP Note 1791485."
This sounds like NWDS is fading away and has got no future. BPM expands in every SP in 7.4, but NWDS stays as it is?
2. You write above:
"The NWDS always WAS a version of Eclipse with SAP plugins. So. I'm not quite sure what your question is.."
IMHO you are missing the fundamental difference between NWDS - an OLD version of Eclipse with SAP plugins - and plugins provided by SAP for Eclipse: The latter must keep track of version changes in the Eclipse ecosystem!
SAP chose the lazy way of providing NWDS as a monolytic bundle of Eclipse from (currently) 2010 
with their SAP plugins. The Eclipse version was already old when NWDS 7.30 was released, but this could be tolerated since most other plugins supported a two year old Eclipse.
But in the meantime NWDS It is still stuck to outdated Eclipse 3.5.2 from Feb 2010. Eclipse is now on 4.3! SAP HANA Studio is on Eclipse 4.3 (maybe stuck there for years, too?)
NWDS, THE java development environment, does not take part at the progress of all the Eclipse plugins.
NWDS has always been based on old Eclipse Version, but this is the first time SAP tells us that it will never update the Eclipse version: "no longer available"? IMHO this is much worse than the "Feature Freeze" in WebDynpro Java that was discussed few years ago. SAP's Java (Dev) Infrastructure is antiquating!
This fits perfectly to SAP NetWeaver Java that is stuck to Java EE 5 from 2006. The world outside SAP is on Java EE 7.
A possible explanation that SAP is neglecting its homework for both NW Java and NWDS is that SAP wants to abandon its own Java platform soon.
Is there another explanation? Why does SAP still recommend WD Java and VC and BPM as technologies that require to use outdated Development tools?
Best Regards,
Rolf