If it's true that Carbon is such a dog that it can't handle multi-avatar gameplay then Eve is pretty much at a deed end.
If that's true, then WoD is completely doomed as well. I think it's more a "we can't have more avatars without reducing the pretty images we have now, so instead of compromise the art we're compromising on gameplay". Which means avatars are pretty much a dead end not from a tech perspective, but from a "We're artists" perspective.
As for the various EVE games being separate, that goes back to the whole "FEARLESS" motto and "We're taking over the world" mentality. It's an attempt at diversification, but instead of actually diversifying and going in a new direction, they played it far too safe and kept the DUST/EVE connection, and using the IP they acquired from White Wolf for their new MMO. Could they go toe-to-toe with games like HALO, WoW, etc? Hell no. They could, however, leverage their existing IP to create a spinoff franchise.
I'll say it right here, right now, and people won't like it; WoD is doomed if it is going to be subscription based. A niche tabletop game becoming a popular subscription MMO? I don't see it happening. DUST gaining momentum after this long, with as many problems as they've had, and on a console that in two months will be "last gen"? Slim to null.
I don't blame CCP though. The only fault they have is that they really aren't agile enough a business, and don't have the manpower for their freakin' awesome ideas. The reasoning looks simple from the outside; why take such a risk with a new game, with new servers, etc. when they could potentially use the same exact server resources for two games? Number crunchers nod, penny pinchers nod, and the marketing team goes "Great!" The problem is, with limited resources (and years of development) DUST is nowhere near where it needs to be in order to be a money maker even after launch, and is about 7 years too late to really take advantage of the console it's on.
Unless CCP makes the big move to PS4 (Valkyrie, maybe?) they might as well bow out of the console business and refocus on PC. Personally, if Valkyrie doesn't launch for PS4 then they're wasting dev resources. If DUST doesn't transition over to PS4, it's as good as dead. If they switch DUST over to PC they might as well just have it as an expansion for EVE (Easy PF fix; new tech is developed to allow Capsuleers to Jump Clone into a soldier, problem solved).
Long and the short of it, CCP is on the edge of a very steep dive if they don't make harsh decisions right now. Looking at the past few years, I'm afraid the "FEARLESS" habit might be too hard to break. I don't blame people for leaving for greener pastures. I enjoy EVE (and I'd be playing right now if my apartment hadn't flooded and my computer wasn't out of commission for another week or two), but I kind of wish they'd take more long term risks without worrying about short term benefit. They're shooting themselves in the foot from a purely business perspective. "FEARLESS" doesn't mean "stupidly following bad plans and making the best out of those plans regardless of how stupid they are because we kind of screwed up and overextended".
Now, on the whole "different games, one client" issue, CCP has the server architecture that runs DUST and EVE. EVE and DUST, however, have different coding. One game uses Unreal, the other uses Carbon. Both share database and servers, as well as a chat client. They are two separate games. Now, once WoD development advances a bit, I'm sure they could transfer over the avatar tech to allow EVE avatars on PC to run just as good as DUST avatars do on PS3. Will they transfer everything on DUST over to PC, an d allow EVE players to fight alongside Dusters? Probably not, because they'd have to build everything in Carbon not just port everything over from Unreal. I'm fairly certain they can get Carbon to work on PS4, since it's PC architecture. If they want to do the full DUST to PC conversion, the PS4 would be their first target (realistically), and if they wanted to port EVE over to PS4 in some way, Valkyrie looks like a good initial testing of the waters.
So it's not just a matter of technology, but business strategy that has to be taken into account. What's the best for the company, what takes less resources, and what has the most potential to see a return on investment? Looking at the current state of DUST (without looking at the metrics), I'd say there has to be some serious questions being asked at the upper management level as to what exactly they need to do to salvage
anything past next year (just speaking of DUST, not EVE).