I glued over 300 different cladding panels onto my house over 10 years ago now and not one has ever failed. I would regard Apples designers and Engineers at the top level and cannot see why the use of adhesives is in any way an issue. Maybe they should sack Jonny Ive for not being a good product designer........
If something inside the iMac goes dead I'd like to be able to easily fix it myself. I'd also like to easily swap out the hard drive with something off the shelf or put in a new CPU.
I get this isn't important to everyone, but it's important to me and I'm sure many others. There's no reason why they couldn't make an iMac that appeals to you and one that appeals to me.