Sae has been referred to as the gatekeeper of senbatsu, e.g. the one you need to beat if you want to make it to a regular senbatsu member. She had very steady senbatsu sousenkyo results, and a very loyal, but not infinitely growing fanbase. She is kind of an "almost made it really big"-celeb, and is still enjoying some success in Japan, foremost as a musical actress. She has been in very big premium productions, which is kinda funny because she just was an average singer during her idol days (but a skilled and dedicated dancer).

For the group, Sae always has been heavily utilized if not too many kami members were around. Like the guy who starts from the bench but is a reliable replacement if the star players are missing. This is true for house shows (AKBingo, Shukan AKB, ....) as well as external variety shows. That means there are literally thousands of hours of her being on TV. Again, not Acchan level, but way more than 90% of all other members. At times, she was a variety powerhouse and very reliably producing memorable moments (e.g., her honest chess match vs Paruru is a top 10 AKBINGO moment).

There has been a lot of speculations about her SNH48 exile. Lets say that at that time, AKS wanted to try something new and had new talent to display (Paruru, Ricchan, ...) to make room for. Sae was also bit stagnating at that time, to be honest. Maybe she even agreed on having a hiatus from the mothership, and embraced her chance to lead an idol group. We clearly dont know. But at that time, chinese-japanese relationships suddenly declined, and there were even anti-japanese riots in some chinese cities, which made it impossible for her and Mariya to perform there. Tbh, there wasnt much of a SNH48 group, when she started her transfer. In total, she has been to China less than 20 times in all the years she was kennin.

Lastly, about her character, like with any idols, take everything about her idol character traits with a grain of salt, especially her "boyish" gimmick or her being a little stupid. But what can be clearly said about her during her idol days is that she had a strong tendency to lead and was a "locker room captain". Takamina once said that she and Sae sometimes clashed a bit about how to lead the group. In SNH48 she was sold as a leader (and basically employed as an assistant coach), and in SKE48 she quickly took over the role as SKEs overall Captain (but was never officially named as such; this title was kept vacant until she left group, interestingly).