Hmm, I have a different opinion by a bit than most it seems. I think the rocket is too low stock, far to easy to drag hard parts, and I think going to a smaller front tire is a terrible idea.
The 1.5" lift of the rear of my rocket acts to make a slightly more forward weight bias, improves agility through altered trail distance, and increases clearance. With another rocket in a certain turn I was still about .5" from dragging anything and he was dragging pegs and highway pegs all through it, the results are real, not perceived. The same effect of altered geometry is achieved as when switching to a shorter front tire, but I am gaining clearance vs losing it like the 130 size tire users do.
Concerning a wider front tire, you can squeeze a wider tire on the front, or run something like a Pilot Road 2 rear tire on the front. Its stickier than our stock front, has a sharper profile, high load rating, and has a high wear life thanks to it's dual compound construction.
The shape of the front will effect agility more than its overall size. Michelin's tend to have a more V shape instead of a U shape like the stock Metzler. As such, I'd bet a handsom sum of cash that a 160 or 170 pilot power 3 or Pilot Road 2 reae tire on the front would improve handling despite the additional width.
The primary concern however will be the distortion of the wider tire squeezed onto a narrow rim. You will be squeezing the bead area of the tire together a little further than intended, the effect will be the tread area is a little taller than the profile would lead you to think. So it would be a lower aspect ratio to buy than you think, example below:
Stock tire nominal diameter - 26.448 inches
180/50R17 nominal diameter - 24.086
180/60R17 nominal diameter - 25.504
Because of the distortion they will probably grow in height slightly to more like areas
180/50 - 24..6"
180/60 - 26"
It will ride fine because the distortion will make it even sharper of a tire than when fitted to a wider rim. The only way to know if the fender will work is to measure the width of the narrowest point of the front and see if there is room.
Same as car tires though, kiss any and all insurance good bye if doing this.