Philosophy has a lot to do with invention rather than discovery, I mean this in the best way possible. It is, amongst other things, a movement to invent better ways to say some things, or to ask better questions themselves. This is not trivial or superficial at all.
The degree of importance on whether it should be simplied or not is debatable. I also think it is nice that you can explain complicated things to your grandmother. Then again, you are not fully responsible for how well your grandmother will understand what you say. If you don't consider this, you have a very naive view on what knowledge and communication is about.
There is also something to be said about how philosophy makes use of language, of ordinary language. If someone who doesn't know much of philosophy or science picks up an advanced math textbook, he won't understand a thing, it will be just numbers and letters and weird signs that are impossible to decipher. He may, however, assume that it is a language that needs to be mastered, that if he study math from the basics, he may eventually get to understand the advanced statements. However, if you pick up a very complicated philosophical work, not only you will not understand it properly, but you'll think you understand it. because you've seen words like "spirit", "work", "love", "communism", "being" etc before and thus, you've formed an idea of them, an idea that might apparently clash with the author's idea. That doesn't mean you actually clash with what the author is saying there, because you are not familiar with his reasoning and the context of other philosophers that talked about the same thing. Just like with math, if you go through the whole path, it will make sense (a new sense) to you.
A lot of people disregard philosophical works, or specific philosophers or trends of thought because they identify themselves too much with some of the words used and it is thought that you can judge someone's reasoning by looking at an aphorism about it. The best part of philosophy, imo, is so violently ground shaking it is only natural that you don't accept it with ease, because rather than the functioning of rockets or something which is outside of most people's lives and that could be only an addition of knowledge, it is about ordinary life and it requires a new arrangement of ordinary words, thus, some sort of abandoment of previous ways of thinking the world. Which is hard.