If the problem with your car is the interior is ragged, I would fix that. Especially as you say your current drivetrain is solid and you get good fuel economy. The devil you know, and all that.
We had a 2000 NB TDI (ALH) and I still have my 2006 Golf TDI (BEW). While the Golf is definitely peppier to drive, the durability and longevity of a properly maintained ALH is effectively unmatched by any TDI engine since then. With a set of nozzles and a mild tune, you could easily match a BEW with a mild tune.
The BEW has cam issues to worry about - while some have had catastrophic issues, mine has been fine with 340k km on the clock, but I have owned it since new. Replacement of the cam appears to have solved the issues due to manufacturing defects, and Franko6 has even come up with some cam bearing oiling mods that appear to help longevity.
Otherwise the drivetrain, suspension & interiors are the same.