I used to be a big fan of ABACUS from Avolution because its really great at letting me extend or come up with my own custom metamodel. So, I spent a lot of time as head of Architecture at a bank doing just that. Then I started to realize what a waste of time it all was because all we did was argue about semantics while the actual work was left to languish. Now, I just follow the standards and live within their definitions,even if I don't always like or totally understand them. Usually I find, after a while, that the metamodels hammered out by standards bodies are better formed than anything I could have come up with on my own. I'm much happier that way!
Now, there is a small minority of EAs who are perfectly qualified to mess about with metamodels, and I'm sure many of them lurk on this forum! However, my experience is that most so-called "enterprise architects" are really posers who really don't understand the discipline very well at all. (These are often spotted in the wild as "PowerPoint Architects") Unfortunately, that doesn't seem to stop them from opining about the ideal metamodel that would only be so perfect if we just made that. one. last. tweak! (Sigh)
It's a bit like a novice musician trying to argue the fine points of musical notation. (Sorry, dude, but Mozart you aint!) Fortunately, the music guys sorted this out a few centuries ago, but we, as a group, are probably not that advanced!
... I feel better now, thank you...
