Q: "Does the MK5 look dated now?"
A: IMO, not when tastefully modded, no. OEM+ always seems to make a car look like an unknown special or limited edition from the factory which obviously boosts appeal and longevity of looking classy.
Sometimes they look dated in low spec, dark colours, when everything is darkened out and they've only gone for the 'black on black' sorta look. Doesn't help, but I don't think they've aged any worse than MK6 in honesty!
Candy white Edition 30's can look particularly fresh for a MK5, with Xenons and a small drop. Again, it's immediate appearance is "this isn't an average Golf" and you have to question it's age/model, rather than it looking 8/9/10 years old from the outset