Learn English – May I say “Time will tell you [something]”

To me, "as possible as it is" is unnecessary. It's already implied. Also, "create a world" sounds more like we're designing a new game, where we can create as many alternate worlds as we want to. The phrase "make the world a better place" is more idiomatic.

So, I would like to offer this:

We design to make the world worth living in.
We design to make our world worth living in.

If you want to emphasize that what you can do is limited, you might say:

We design to make the world as worth living in as possible.
We design to make the world worth living in, and as much as possible.

But that sounds a little wordy, and a little clumsy.

If you want to emphasize that you will do everything that you can do, you can also say:

We design to make the world worth living in, every way we can.

But that might not be what you really wanted to say.

The second sentence does sound unnatural. "Tell" needs an object in this case.

The first and third sentences both work, and mean almost the same thing. The third sentence focuses on telling you something. Out of context, it sounds more like a direct warning -- "Hey, pay attention to this, car mechanics are trouble!" The first sentence sounds more like a remark or opinion -- "Speaking of car mechanics, I've met a lot of dishonest ones." It might be agreeing or disagreeing with another sentence. These are only small differences, though.

Also, you might want to put a "the" before "car mechanics". It makes the sentence sound smoother since you're talking about specific car mechanics (the ones you come across).