The one thing I noticed reading the messages from kids on the CBBC memorial page
LINK, was that a great many of those messages from kids include things like
"I'll keep watching, but I'll never forget her" and "
The Sarah Jane Adventures will never ever be the same without her", and others in a similar vein, most of which imply a belief/hope that the show will continue even without her.
Sure, there are a couple that say that they don't think the show should continue without Sladen, but by and large the vast majority seem to indicate that the show will/should go on.
And there are even a couple of entries like this one:
"There's never going to be another Sarah Jane like Elisabeth." Not that there won't be other Sarah Jane Smiths, but that none of them will ever be as good as Sladen was in the role. It essentially implies an acceptance of the idea that there will be other/future Sarah Janes. Sounds to me like while kids will certainly miss Sladen, they're expecting a lot more adventures with Sarah Jane, even if that means accepting someone else in the role.