Blimey, this thread grew quickly - it's interesting though.
Personally I enjoy the new episodes (although I've not seen any of Season 23), but I generally view the show in much the same way I view music. There is plenty of quite shallow music that is pleasing to the ear, and there's nothing wrong with enjoying it, but in terms of quality standards can't compare to the depth and complexity of more intelligent music made by people who are proficient with their instruments and care about their composition. In the end though, it's all genuine, and has to be taken for what it is.
I will have to admit though that the show isn't the same anymore. I would say from what I've read that this is because not only has much of the personnel involved left for other projects, but the man (Al Jean) tasked with overseeing the shows concept doesn't aspire to achieve the standards that it used to reach back in the 'classic era'. Unless the staff is changed, there can be no significant change to the format of the show - they're writing what they think is good. It still has plenty of enjoyable moments, and I'm happy to watch post-classic episodes, but unless the people involved with the show take drastic action to improve the quality rather than just sitting back and letting it drift on as it is there won't be any change.
As for how the show has reflected changes in society - I definitely agree that it's contrary to the shows ethos. I find the overused celebrity appearances and constant 'internet references' as probably the most obnoxious points about the show these days - if they concentrated more on sound character-driven plots again, that would definitely make for some improvement.