Although Jim Parsons enjoyed Sheldon's final storyline, Johnny Galecki felt differently after he read the script and what was in store for Penny and Leonard.
Both Kaley Cuoco and Johnny Galecki had mixed reactions to Penny and Leonard's finale. Penny announces that she's pregnant, although it seemed as though that wasn't in the works for the two throughout the series, and Cuoco was onboard with this decision. Reading the script, Galecki revealed he didn't quite understand it at first.
“The pregnancy shocked me. I didn’t get it at first. Molaro and I talked about them maybe not [being pregnant]. The main takeaway is that these friendships will continue; the writers didn’t want someone to move away. We wanted to leave the audience with the idea that these friendships and the love that they have continues.”
Steve Holland, a showrunner on The Big Bang Theory seemed to agree with Leonard, stating that the storyline was very abrupt, and that there as no proper build to it. He admitted that it could have been handled differently in the final episodes leading to the finale.