If I may defend Cinos a little here.
First of all, it is important to mention that when I listen to trance, a lot of it is Suomi stuff. Also, I do not believe it to be boring or monotonous.
However, if people say that there is too much change in suomi, it may be taken to the extreme and imply that there is only change in suomi. If there is only one thing happening (here this one thing is change), then the word monotonous may be applied.
Feel free to flame me.