I Need Your Opinion And Suggestions, Is A Rock Garden Worth The Time?

We have owned our house for over 12 years and for all those years this area has looked just like this.  We believe at one point there use to be a rock garden there, see the big rock?  Now it just gets mowed around and looks horrible, is the attempt at making it a rock garden worth it?  Do people even have rock gardens anymore?

I would really like to make this area look nice (at least attempt it one summer).  I've always admired other people's rock gardens and I have the prime spot, however I have no idea how much work they are and I've got limited time.  We even bought a pond basin from my sister with the plan to make a rock garden with a water fall that flows into the pond.  It's situated perfectly on the hill for that.  I talked about Koi fish too, but let's get real, I live in Minnesota TOO cold at night and what would I do with them in the winter?

I thought I would research rock gardens over the winter to see what kind of soil and plants are needed to make it work, but here I am, it's already June, so I'm asking for a crash course and suggestions.  Bare in mind that I have killed air ferns before.  Who knew they needed water too, I thought they just thrived on air, thus the name AIR fern.  Do you think I should wait until next year?  Is it something we need to leave to a landscaper?  Do we need to draw up plans before we start?  UGH! I'm dabbling into the world of the unknown.....HELP, please!!!!