Not too crazy about the last episodes

It's life. With all its warts and problems. When a sitcom ventures into real life, it's not for everyone, but, as I have experienced in my life, things like this does happen.
I tend to think that this show, as others of the highest caliber, are not afraid to delve into "real life".
It's what makes good sitcoms so good.

What kind of preachiness did it delve into? I might not bother watching the final season if that is the case.

I really liked the final episodes.

you wanted jokes after the father died or something?

I didn't see anything preachy about it, but I wasn't crazy about the last 3 either. They were pretty depressing.

And the adult Sheldon was just being an ass towards his wife (and kids). Not even remotely funny. (Yes, i've watched TBBT.)

Yep, it was really dumb letting George die. This destroys the whole series, cause it isnt fun anymore. When you rewatch it you just think about the last episodes. It destroyed the whole rerun/syndication of this show. Noone knowing the end will watch it again. Never kill a major character of a sitcom. You could to that with SciFi (at ST TNG for example). but not at a sitcom, cause it destroys the whole purpose of having fun. For me this series died with last episodes. And not just for me. It was simply a stupid business decision which kills this series for future reruns ("Isnt it the series where the father was killed at the end by the authors?"). Amazing how incompetent movie producers came this days.