What features are missing from the language? How long has it been since you've built an application in ColdFusion? It's certainly not very popular, but I haven't seen anything in say PHP or Rails that I couldn't do in CFML, and it has some neat features that set it apart (for example, built in SQL engine to query an in-memory recordset)

I just did superficial Wikipedia research. Might you have an aversion to CFML, which is like a COBOL dialect built out of HTML tags? But CF code doesn't have to be written that way; there is also CFScript which superficially resembles JS. You can wrap it between <cfscript> tags:

  <cfscript>
  function Sum(a, b) {
      var sum = a + b;
      return sum;
  }
  </cfscript>

This seems all-right-ish at first glance (to say which, of course, I temporarily lock my Lisp programmer hat in my desk with keys, which I then throw across the office to retrieve later). Are the semantic problems with CFML/CFScript (say, along the lines of the famous issues with PHP?)

Sounds like it's been a LONG time since you looked at ColdFusion - I encourage you to re-visit. A lot has changed since the late 90's...it's a great language, not a nightmare at all.