Been there, done that, had a dish that was visible from the street. Don't take it with you; D* will supply a new dish.
Don't make yourself nuts about it. Plan on leaving it as-is. Don't mention the dish in the listing, or say anything about it to prospective buyers, unless they directly ask about it. To a buyer, it's a cosmetic issue. If a buyer really wants it removed, they can put it in the punch-list of items-to-fix prior to closing. You can remove it, patch the roof, and sell the used dish+lnb's on eBay or craigslist, or on this forum's classifieds, or possibly to some dealer on the web.
If you remove it now and your patch leaks, it WILL impact your potential for sale. Any decent home inspector (or observant buyer) will find the water damage. OTOH, if the buyer wants it removed/patched, that probably will happen after the imspection and any potential patch problems will be theirs, not yours.
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Something else to consider: Not sure about your area, but I've known of cable companies who would not install service to people who could not provide 2 months' of LOCAL utility bills. For example, Comcast cable in Danbury CT. I had a neighbor who moved into the area from 45 miles away (and from NY state). They had no LOCAL utility bills, when Comcrap told them to call back in 2 months, they immediately called the sat installers. If your local cable provider has a ridiculous policy like that, then some buyers will find it a convenience to have your dish already there.