Whoa. That is a crazy assertion. First, not many languages have been designed with the IDE as a concern, and second, all the industrial PL design teams that I know of definitely work closely with their IDE team to ensure harmony between tooling and language. I'm a bit more radical, all of my recent languages have been heavily tied to the IDE, to the point that there is know real boundary between the implementation of the compiler and IDE.
Working closely with the IDE team is a good thing, but core language developers focusing on the IDE and the language in the same time can indeed lead to some compromises that hurt the language.
