What's to say?
It seems like the decision was to go back to probably their most successful set. I don't know about successive sets, but I do know that the Crimson Strike set originally sold out. Granted, this was their first ARAH set and the numbers were lower than later sets, but still, a sellout is a sellout.
Crimson "whatever" has always been a good, safe bet. You can usually do well with something in that scheme, so I see the logic behind trying to recapture that hit with the 25th molds. However, I get the feeling that MC wasn't expecting quite the backlash they have received around this set. The set comes off 1 of 2 possible ways, in my mind, in regards to the reasoning behind it. Unfortunately both possible ways are not very flattering for MC or the future of ARAH/25th sets.
1) MC has begun to let the ARAH side of the Joe con slide. With the Transformers con taking a more predominant spot in their business (& probably larger), it seems that Joe fans are getting stuck playing second fiddle. That means the majority of their resources are going to TFs and so a quick and easy convention set was decided on. That set was basically a rehash of an already made set, but using 25th figures. If this is the main reasoning behind the set, then it is sheer laziness and greed.
2) MC is running out of ideas for large ARAH/25th sets. The model for these sets seems to be static, with no room for change. 15 figures with a heavy emphasis on army builders/mold reuse, and a "set" price in the range of $270-$300. This leads to very limited selection for possible sets. GI JOE basically only has greenshirts, although I think you could do sea or air sets of JOEs with just changing the heads and keeping a standard uniform body. I don't know if that would do well. So that basically leaves Cobra as the main thrust for most sets. Whether it is Cobra, Dreadnoks, IGs, whatever. However MC has already hit on CGs, IGs and Dreadnoks. Then they started in on "new" subgroups or characters that seemed to go over well in some cases. The problem with "new" subgroups is that you are taking a big risk that fans will want them or not. Ginning-up an existing subgroup is a safer bet.
It's funny really. MC had been moving along with the JOE licence and then picked up the TF licence. At the start, they received a lot of hate from TF fans who hated the business model and felt that TFs were playing second fiddle to JOEs. Then slowly the TF fans started to accept this new way of doing things and are now pretty happy with how the convention is run.
The switch is now to JOE fans who seem to be playing second fiddle and getting shunted around willy-nilly.
My suggestion to MC is look at your business model for the JOEs. Maybe it is time to consider a change. 15 figure sets may no longer be sustainable as a model for the JOE mythos. You were flexible with the TF sets, at the beginning, to some degree, maybe it is time to think of something similar for Joes.
That, or as others have suggested, start mining the existing subgroups you haven't done (TF, PP, SP, NF).