Congratulation on you new acquisition! Its a beautiful watch. Do share some pictures with us.
I would not consider the latest generation AT's to be of a lesser build quality. IMHO All of the three generations of ATs (from a bezel point of view) had their inherent pros and cons. I believe IWC tried to rectify the shortcomings of each, and since there is no perfect solution in engineering, only trade-offs, something new popped up with each new generation.
Gen one's inner bezel bezel: PRO = cleaner design with inner bezel with no chance of accidentally rotating it as the crown got disengaged underwater; CON = Turning the bezel could be a challenge for someone wearing gloves
Gen two's bezel: PRO = IWC made it easier to rotate external bezel through a conventional bezel design with sapphire disk lumed on the underside to prevent scratches; CON = You could rotate the bezel accidently, unlike the earlier generation (this was the trade-off!)
Gen three (current): PRO = IWC’s SafeDive system that can be controlled like a conventional external bezel design (but rotates an inner bezel) with the added functionality that will prevent accidental rotation while at the same time making it easier to rotate the bezel unlike the first generation ATs; CON = the thing at 9’o clock may not be adding to the aesthetics according to some of us (this was the trade-off!).
That said, I second your view on the earlier generation AT's - I think a simple rotating external bezel is the best trade-off while at the same time looking really good! If IWC could make the 9’o clock mechanism a little more inconspicuous (and I do not know if this is possible), while at the same time retaining the SafeDive’s wonderful functionality, it would make for a stellar package.
Just my 2 cents
Sumit