A truly anonymous coin will be designed with anonymity from the beginning.
I'm not sure you haven't put your foot right in a great big technical cowpat here. You might know what your talking about and you might not have a clue but I'll give you the benefit of the doubt.
From a software engineering point of view though, integrating functional layers like your suggesting is sometimes a good thing and sometimes a complete disaster because you're creating a coupling that you'll be forced to live with for the rest of the coin's life. You would only ever do that if you were absolutely sure you never wanted to evolve those two layers independently of each other.
On the other hand, keeping them separate (the anonymity layer and the blockchain layer) has some huge advantages. In particular, as we've already seen, it allows the blockchain layer to retain legacy compliance and compatibility with commercial APIs while at the same time liberating the anonymity layer so it has the capacity to evolve rapidly in response to real world use. We've already seen this happening - we've seen how much flexibility there is having the functional layers decoupled. If you weld them both together, your "stuck". You can't evolve the properties in one without being ball and chained by legacy interfaces in the other.
You say that the RC2 and RC3 forking issues belie a fundamental design problem i.e. the decoupled model. Again, I think you've made a very big mistake here.
I saw it the other way around - i.e. as evidence that something "real" and successful was going on in this project. The forking was nothing. Sure, it made a big splash and as the dev correctly expressed - was "unacceptable" but it does not - as you contend - stem from the decoupling of the anonymity layer from the blockchain layer. It's simple software development - original work being consolidated. If you don't want to see that kind of thing then pick a coin that's going to have the same features in 6 months time as it has today.
So in summary I don't think there's any basis for such a point blank appraisal. I think it's highly superficial, lacking in technical depth and not remotely thought through. In my opinion, DRK has got it right and the others are all heading straight up a cul-de-sac that's going to leave them like beached whales - having a reasonable anonymity model but with no audience.
In addition to all of that, the decoupling principle goes right back to the original Darkcoin mission statements - see section 3 ("Why is this approach the right one") here:
https://medium.com/@simon/the-bright-side-of-darkcoin-a923facddc3cThere is a definite need for an implementation that solves the anonymity problem with a decentralized approach and proven technology.
Note the phrase "proven technology". Markets like "proven technology" but they also like leaders, so again the decoupled approach makes sense where the coupled one doesn't. This stuff has all been thought through in far more depth than most 5-second posters on here realise, with due consideration being given to optimising both technical and end-user (or "market") priorities.
Under these circumstances, you can't really blame the devs for sticking to the original "plan" and mission statement.
It was a good one then and it hasn't been bettered.