Its an OK sunset and the horizon looka a bit bowed but the problem is with sunsets is that we have all seen hundreds of glorious sunsets, maybe thousands - and there's not much to prefer one to the other.
I tend to agree with The_Traveler. We have all seen hundreds of sunsets and sunrises and the real trick is to capture one that grabs folks attention and that is very hard to do these days.
One thing I have found when shooting sunsets is that often the best colour comes after the sun is down below the horizon and the pinks that are in the sky start to flood the clouds at certain elevations. My problem is that I have never been able to figure out what those "elevations" are, or how to predict when this "flooding" will happen.
Just out of curiosity, I did a Google search on "sunset images" and got almost 200 million hits, so that gives you some idea of what you and I and others are up against photographing sunsets. The real key lies in whether or not you like the image and if you do, then that is what really counts. As an artist, it is your image and yours alone.
I am not sure how you shoot sunsets, but here is what I often do - I start as you have done and take one shot when the sun is just above the horizon by maybe one or two widths of the sun and then I continue to shoot every 1 to 2 minutes (30 seconds sometimes), until the sun is disappeared and then I wait and see if the colour from the sunset will be reflected in the clouds above the horizon. sometimes this works, sometimes it doesn't. A lot depends on where you are in the world and thus, how long the twilight lasts. Sometimes, I will shoot a quick 3 or 5 exposure HDR set and see what that gives me. The real key, for me, is to experiment until you develop a style for these images that you are happy with.
As far as the image itself goes, I have to basically agree with WesternGuy there...I do think it's a rather lovely image (perhaps a bit over-saturated), however I just can't say it's anything terribly special either as you can find thousands and thousands of similar images with a simple Google search. Goodness knows I've shot plenty of similar images myself. That said, I also have to agree that it's your image...unless you were shooting this for a client who wanted something special, then as long as you're happy with it, that's what's important.
As far as the upgrade goes, my suggestion would be to ask yourself -why- you want to upgrade. Is there a specific reason? Is there something with your current camera's capabilities that you're no longer happy with? Newer cameras of course have higher resolution and many/most have better low light capabilities these days, so if that's a concern, then sure...could be time for an upgrade. On the other hand, as both a photographer and a musician, I also know that a lot of folks tend to get G.A.S. (Gear Acquisition Syndrome) from time to time...they see all the new toys available out there and start to feel as though their own gear is somehow no longer adequate.
With all of that in mind, my suggestion would be to decide -why- you're interested in a new camera. -IF- there are indeed features you could/would actually use, by all means upgrade, however remember - new gear won't make you a better photographer. The truth is that there are people out there who CAN take really amazing images with little more than a camera phone and conversely there are folks who own the most expensive gear money can buy who couldn't take a decent image if their lives depended on it. At the end of the day, it's not the camera, it's the person using it.
I like the left side of this because the silhouettes give it some addional interest. I think that would have made a better focal point or foreground point of interest than the water which is a bit dark and overwhelming. Great colors in the sky and clouds. I would have been tempted to move to the left and shoot this in portrait orientation with the silhouettes near the bottom and the sky taking up most of the shot. As for sunsets being done before/already/to death, so what? Each sunset is a unique experience for those who are enjoying it and worth capturing if only for a reminder of the beauty.