Hi,
I'm not exactly a fan of D&D, but they're not that bad. They're certainly no more childish than "TISWAS" was in its day, or "Number 73" was in the eighties!
If you really want dumbed-down TV, you need look no further than some of the

that C4 still turn-out, e.g. Big Brother (and all its associated spin-offs), Eurotrash (which actually used to be fun, but is now just

), the whole T4 strand of presenters (and most of the programmes), and all the daytime makeover/DIY/be a better person kind of dross they air.
ITV1 are just as much to blame, with all of their crap. "I'm A Celebrity...", "Hell's Kitchen", "The World's Worst/Best/Least/Most.... whatever", "You've Been Framed", "Ant And Dec...", "TV's Naughtiest Blunders... ", "All Right On The Night...", "Recoats", etc, etc.
Only Channel 5 has actually improved (for the most part). From a channel that used to show a lot of tat, it's actually my fave terrestrial station, and shows a lot of quality material now.
Pooch