she was the only reason left to follow Smileage...
With statements like this, I have to question whether you followed S/mileage or only followed her.
That's not necessarily a bad thing, but it's like saying Morning Musume was dead when Rika left.
To be honest, Yuuka's presence in the group has been having less and less impact outside of their musical performances.
Sure she was the star of many of their songs, but on TV and internet appearances she's been something of a bump on the log.
Compared with Ayacho's eccentric, art-loving leader and Kanon's idol wota/professional troll/Cinderella personas, Yuuka's "I like puns" thing hasn't stacked up well.
I love Yuuka, and recently when I was deciding which S/mileage member was my favorite, it was a tough decision between her and Ayaka.
But when I did finally decide on Ayaka, it was mostly due to the reasons above.
In the end, I think maybe you meant "she was the only reason left
for me to follow S/mileage".
There is an important distinction between that statement and the one you made, which says to me, "this is what I feel and everyone else should feel this way too because it's the objective truth".
When there's
six other girls in the group, many of whom have personalities that stand out more than Yuuka's, how hard is it to
find a new reason to follow the group?
As a strong subscriber to the idea that the group is far stronger than any one member, I'm afraid I just can't accept the premise that the group is now dead.
I will however say that I agree with this sentiment:
Have a good study Yuuka! Make it count.
I seriously hope she makes the best of her decision.
I'm just afraid she'll just turn into the prettiest OL in the office:

Go get 'em, Yuuka!
Show the world that Egg Quality!