http://eigenjoy.com/2011/03/02/clojures-keyword-can-fill-up-...
It's just something you need to be aware of.
That said, some of these issues (slow collections, talent availability, tools) have nothing to do with language complexity and might affect almost any relatively new programming language if the implementors didn't consciously work to counteract it.
Revised: fine ok maybe a bit harsh. My opinion is that language design would be extremely influencial over how people implementing collections/tools/compilers go about doing their work and what the end result of their efforts would look like. In fact they probably are more telling of a design than anything else. That last part was sort of bs guesswork but it sounds right. Happy now?