In my mind, the greatest strength of awk as a scripting language is its widespread availability. Whether you're using a modern Mac fresh out of the box, GitBash on a windows machine, or talking to a router over SSH, you can be confident that some version of awk is close at hand. The cost of this ubiquity, however, is extreme fragmentation. As is usually the case with GNU extensions, gawk provides a variety of shiny baubles which
absolutely cannot be counted upon if you want to write a portable script. As a result, they're traps for the unwary to at least the same extent as they are handy tools.
There are a variety of small features which could greatly enhance the flexibility of awk, including things described in this article and more ambitious ideas like making associative arrays first-class values, but if they aren't broadly supported, I don't imagine they'd have much impact. If I need to install a specific version of awk to run a script (and I have the ability to do so), I could just as easily install one of dozens of other capable scripting languages instead.