Like you said: It's still best-looking laptop in the market. And if it ain't broken, don't fix it. True, MBP's have had their share of the problems, but they aren't really due to the design. They could fix the various issues while leaving the appearance as it is.
To be honest, the design is not only getting old but it also is not that functional.
The MacBook looks more modern and is a lot more functional.
AL MBP Design issues;
1) Looks like a RAZR
2) HDD difficult to service
3) Dents, scratches, and attracts smudges
4) Shields WiFi signals
5) No docking port on current design
6) Little metal clasps on latch too fragile, Mag clasp like MB is better
7) Keys are too easy to accidentally pop off and too tapered.
8) Too much wasted space below keyboard.
9) Needs two mouse buttons or functional multi-touch pad.
10) Keys still smudge display screen.
11) ABS plastic, carbon fibre, housings are more durable and lighter.
12) Silver is sooooo 2000.
Do you need more reasons. Sure some of these are minor but if I am going to spend $2500+ on a laptop, I want a state of the art design.
Apple can do better. They just haven't focused on this product in awhile.