I see a difference in priorities. A sunroof makes a car's interior appear friendlier, brighter and gives that hint of open air.
But it is not for the extreme frugal types. Not only is it an add-on expense at purchase, it will also promote corrosion because the drains go into the rockers.

 

Brighter is no good, extra glare reflecting off the back of my glasses and in to my eyes. Extra sun = extra heat as well!

Open air circulation is the only benefit of a sunroof, period. This does not outweigh anything else, unless you park at make-out point and want to look at the stars!.

 

My 2001 leaks rain water right down to the fuse box and onto the floor on the driver's side. I tried to have the windshield replaced, and the installer pointed out some signs of rust around the top of the windshield I hadn't noticed. He refused to do the work because he was afraid of rust damage all around the windshield, creating holes under the moulding and letting rain water in. I might just have a close look around the whole windshield, sunroof and other windows and see if there isn't any bubbling in the paint, indicating some water damage underneath.

 

I know this is an old thread ...but just to confirm the sunroof is the issue I had the problem of the passenger side filling up with water with heavy rain I sent time checking everything including the sunroof drains (which were clear btw) after exhausting all possibility's I ran a small bead of silicone around the sunroof rubber to the body of the car ...problem solved the aperture on the drains is not enough to drain the water sufficiently away imo ..if I want to use the stupid sunroof ill need to buy a new seal

 

Another prime area for water infiltration are clogged drains in both the door bottoms and the rocker panels. These must be clear or water will back up into the vehicle's interior.
On most Mazda's I am familiar with, the door drains have little plastic doors which acts like check valves to allow moisture to escape from inside the door but not come up from the bottom. These need to be opened and cleared from time-to-time. Again, a shot of low pressure compressed air is the easiest, fastest way to make that happen.