Couple of comments from someone who has a lot of experience with both gas & diesel.
I'm a trucker. I have run all 48 plus the lower 6 of Canada for 30 years & have almost 3,000,000 miles logged I appreciate diesel engines. I know their advantages & disadvantages
I'm also heavily involved in the old car hobby. I have a 22' enclosed car trailer that's outfitted with quite a few "field tools". It's 4500 lbs empty.
When I bought my '04 Super Duty, it was a no-brainer to choose the 6.8 V-10. I run my equipment as long as it's still financially viable to do so. Ford was in the middle of the 6.0 fiasco, so that was not something I was going to fight for 20 plus years. I tow my 8-9k lb trailer 12-15 times a year with trips as short as 10 miles or as long as 500.
I went with gas not only because of the 6.0 deal, but also because I only live 2 miles from where I work. That may have been a determining factor even if the old 7.3 was available. Short trips will kill diesel engines. 180k miles later, I have no regrets. I service it every 5k with 6 quarts Mobil 1 5W20 ($30 give or take) & a $4 Motorcraft filter. My buddy with a 7.3 diesel does his every 7500 miles with 15 quarts of 5W40 synthetic Rotella ($90 +/-) plus a $12 filter. Service wise, advantage gas. Neither engine has required significant repairs, so as of yet, no comparison there. Neither truck will be sold, so resale is also not applicable.
My truck was equipped exactly as I wanted it except it had 3.73 gears. I knew going in I'd swap gears. When the truck had 36k miles, I spent the $1k for the gears & swapped to 4.30s. Again, no regrets. I realize I'm comparing two different engine series here, but I only lost 1.5 mpg highway (staying @ 70 or below). I actually gained .5 mpg in city as long as I don't "play". Towing; I gained significant mileage. The 4.30's put the engine in it's sweet spot in 4th gear at 60 mph (about as fast as you should tow a loaded trailer with trailer tires since they are rated @ 65 mph). Throttle position has as much to do with fuel mileage as rpm does, imo.
All this being said: that 7.3 gasser is going to make quite a few people happy. Not everyone wants or needs the upkeep & expense of a diesel. I, for one, will look at that engine when my '04 gives up.