I have also been disappointed in the quality of my G's, but still love them!
Agreed that all can be fixed.
I assume that you don't do your own oil changes based on the front shots, might want to have a word with the people that do, or start doing them yourself.
The headlights on my 04 coupe look like crap too.
I use 3M's plastic cleaner every few months to keep them looking good. It's very quick and ez to use, just follow the instructions.
Have also noticed that the rubber seals do pop off ez, so makes since over time they will start flopping down.
As for the interior, do you use a sun screen in the front window to cut down on heat?
Are your windows tinted? The interior heat may be too much for the glues....not sure.