I think you could say that "work life balance" has worked its way into the Japanese lexicon as foreign loan words. So
ワークライフバランスが難しく(厳しく)なってきています 。
or
ワークライフバランスを保つのが難しくなってきています。
or
ワークライフバランスを実現するのが難しくなってきていま す。
If you are determined to avoid katakana, you could probably say something like
仕事と家庭の調和が難しくなっています
but I think the katakana works better.
(You could also do as Mike suggested, and that would be equally understandable).