I've been working on and with Kerberos and PKIX for decades. I don't find ASN.1 to be a problem as long as you have good tooling or are willing to build it. The specs are a pleasure to read -- clear, concise, precise, and approachable (once you have a mental model for it anyways).

Of course, I am an ASN.1 compiler maintainer, but hey, I had to become one because the compiler I was using was awesome but not good enough, so I made it good enough.

I'm curious what made it a nightmare for you.