My major problem with English is not so much that I can't express myself and communicate what I want to get across; it's just that it takes so much work to do it. Certain ideas are really easy to express, but those aren't necessarily the most basic ideas. Other natural languages are the same way, but I have a suspicion that English is about the least consistent, most mixed-up language there is.
One extremely basic verb-type idea that isn't used much in English is best translated as "involve". You can be involved in an action or an action can involve you (or your dog or your car or any other noun-type idea). In Japanese, one of the most common words there is is "wa". "___ wa" is often translated as "as for ___", which is really the same as "about ___", "with ___", or "involving ___". All it means is that the object in question has some unspecified connection to the verb. So I could say, "Involving your car, we have a problem." In Japanese, it's considerably more simple (or is it "simpler"?): "Anata no kuruma wa mondai aru." ("You no car wa problem aru.") This basically means, "There's something wrong with your car," but with a little more focus on the car instead of on the problem.
The reason why I've been using forms of the verb "involve" instead of prepositions like "with" or "about" is verbs are a much more flexible, more universal part of speech. It's easy to make up a new verb, but have you ever tried making up a new preposition? What I'm getting at is that, when designing a new artificial language, you don't need prepositions (also called particles in some situations) if you handle verbs well.
As a simple example, the word "with" can often be replaced with "having": "I want coffee with sugar," or "I want coffee having sugar." The second sentence sounds pretty awkward in English, but if you change it to "I want coffee that has sugar," it's much better and you're really doing the same thing still.
What stinks about prepositions is that we have a very limited number of them and, like I said, we don't like to make new ones. On the plus side, they're short and kind of vague, so you can use a handful of little words to do a lot of work. So when making your own language, just be sure to include a handful of really short, really flexible verbs, and you don't need no stinkin' prepositions!