As much as I love Perl, it has a reputation of being exceedingly difficult to parse accurately, hence IDE support will never be great. There's also probably more demand to support hipster languages than last generation's work horses.
Perl is very tricky. Its syntax is undecidable, so unless you run the program it's not possible to construct a syntax tree given input (in the general case, it's possible to make heuristics that will cover 99%) so it requires more brain power compared to easy-to-parse languages like python.
There are several perl extensions from language support, general debugging etc. Though this can probably be improved, I think it has a lot of the same challenges that Ruby support has. A limited user base, and a comparatively flexible language.