The problem with the show changing course is that they really don't have the setup for it. I don't know if it's the actors, writers, directors or whoever is at fault (most likely a bit of everything), but the show is in all honesty terrible now - even if you accept that it's no longer a comedy. If they completely stopped trying to make it a comedy it might actually be a lot more enjoyable really, because the "jokes" they put in are terrible and they keep repeating them. Just to mention a few that really annoys me:
- Screaming. It's something they've done more and more over the past seasons and I never understood in what possible way it was supposed to be funny.
- Lily saying "you son of a bitch" over and over again. Now, I don't mind a catchphrase (the show's success if pretty much based on Barney's catchphrases from when it was actually funny), but despite saying it so many times the delivery of the catchphrase is still incredibly poor.
If they really wanted to make it a drama - like you suggest - they need a decent story, which they really don't have right now. The show has been treading water for a long time now just milking the success - what has actually happened over the past few seasons? The writers have run out of ideas, which is especially evident by the small side-plots this season that takes up a lot of time but lead absolutely nowhere. Robin and Barney being afraid that they're related wins the prize so far, but the whole "senior citizen"-nonsense in the latest episode deserves a special mention. Still going to watch it though, just to see how it ends - it's only 20 minutes after all.