DS2 is an academic scholar at T and is taking his GSCEs this year.
There is a new head of scholarship (or something) this year, so things might change a little bit, but so far, literally all that it has meant for DS2 is that he has had an "academic scholars breakfast" once a term where presumably they chat about scholarly things. I think there might be a vague theme to them.
There was one evening talk by "inspirational people" that all the scholars were told they had to attend. But the talk was open for anyone to go to, so it wasn't just for them. And when there was the optional 4th form project, it wasn't optional for the scholars, they all had to do it.
He does have a "5th year academic scholars trip" next week - I got the email today - but this is the first one ever. It's a day at the imperial war museum, so it's not like it's anything terribly special.
As for GCSE choices, DS2 wasn't given any extra choices, nor as far as I know was he given more freedom of choice than non-scholars. He had exactly the same instructions and choices as DS1 (not a scholar).
Essentially everyone has to do maths, 2xEnglish, double or triple science (depending on which set you are in in 3rd year), one MFL and one humanity, and then there is a free choice for the other 2 or 3 choices. They try to let everyone do what they chose, and I haven't heard of anyone being told no, sorry, you can't do that combination - I would have thought that was very rare, and for very unusual combinations. And the top 3(?) maths sets do further maths GCSE, but that's independent of whether you are a scholar.
DS1 (never done any singing before) has sung in loads of stuff with the choir - with the ENO; at the royal opera house, royal albert hall, RFH etc, so if your DC is talented at sport or music they will definitely get all sorts of opportunities even if they are not on a music or sports scholarship.
So to summarise, I really don't think that non-scholars miss out on very much at all. I hope that puts your mind at rest a bit.