The promotion was shocking - although she also did an amazing T4 Music thing which actually got a lot of positive feedback on Twitter. If I remember correctly it was the same week that Avril did her Live Lounge and that week was when WTH shot up the chart to #16. Still, #16 for a lead single and #9 for an album - after 3 consecutive #1s - is not good, I agree.
Smile isn't particularly age-appropriate but I think the average listener of Radio 1 doesn't look for that - look at Rihanna and Katy Perry. Still, I see what you mean about it being the same old, same old - all the MM material is like this and all 4 of them are basically the same song with different lyrics. I think the only MM song that was actually something NEW was I Love You and that's the song that always seems to be forgotten, yet I think it was the best choice for the lead single. Goodbye Lullaby has many good songs but it doesn't have anything that could match Complicated, My Happy Ending or Girlfriend.
I put it down to lack of awareness of the UK market and I really hope Epic handle this better.