FWIW, I had sunroofs on Mercedes sedans staring in the 1970s. Early ones were manual, but later ones were electrically operated. I never had major issues with any of them in 35-40 years of using them. Occasional cleaning and lube of the track was about all we had to do. I might have had a repair one of them, but it was not major. So, it was not rocket science to build one that seals properly and operates smoothly.
But having said that, the Tesla sunroof is different from the ones I had on Benzes in two important ways that might make the comparison imperfect. First, the moving piece of the Tesla roof is physically larger than any I had before, as is the opening. Second, the Benz roof panel slid under the roof at the rear, and that was steel, whereas the Tesla moving piece is lifted up and over the rear section, which is another sheet of glass. I do not know how those design differences might affect leak rates, noise or reliability.
My Model S has a sunroof and I do enjoy using it occasionally, mainly in pleasant weather in the spring and fall. I suspect the number of actual hours I use it might be smaller than I imagine....