No, it's about restoring so that it can have a modern use and educate better through living history. My hometown is Lexington, MA, and we keep the battlegreen basically as it was, and every year we have a reenactment.Also, what would even be that interesting about a restored collosseum? Isn't the point its history? Like as far as modern domes go the building is kinda tiny. Its not like people like modern collosseums much apart from sports fans. Isn't that kinda like asking who would like the Venus De Milo with robot hands? Well given the proposals for Notre Dame I guess thats keeping to form. Ah well, no stake in it myself so Rome do Rome I guess.
As a side note, if you do want to see the Lexington reenactment, I'd watch a rehearsal instead of the official one as you don't have to be up at 3AM and you can actually see it without being a pro basketball player (the crowd gets 10 people deep on the day of, so get there hours early).