On the people who invented the kanji not thinking about making it easier, it did make things a lot easier. For China. A phonetic writing system was unthinkable at that time, people from two parts of the country didn't understand each other talking, so the ideograms did the job.
@Zlejedi, I used to hear that all the time, they will hate at the uni if you watch anime and study Japanese... but my course has like 50% anime or manga (or both) fans, one JRPG fan (apart from me) and some of the senpai we've talked to also like it.
On a sidenote starting today I know that it's 韓国語がぜんぜんわかりません。 (since I had written it with を earlier in the thread).