The GCSE courses are designed to be completed over two years. Having taught them in schools I think that's more than fine, in my subject of MFL anyway. All my English colleagues were fine with a two-year KS4 as well. I think if you did it over three years, in some subjects (English springs to mind in fact) you would be so bored of ACC (or whatever) after three years. Doing three years of English KS3 means you can look at a wider range of texts such as those from other cultures too.
Yes in an extra year of MFL you could go into the grammar in more depth, do more work on the culture of the country; but tbh you could do that in year 9 anyway (and we did tbh). Often in GCSE years the focus (from the YP) is “will this get me a better grade” so not really a time for discussion of the fall of the Berlin wall tbh.
In my schools (and I am sure this is not unusual) the DC rotated round the creative subjects in KS3, a term of each, so if they were choosing options in Feb of year 8, it would have been more than possible for them to have completed just a term of study on (say) textiles or music – and that was last year. Based on that are they going to know that they don't want to continue it?
And it is IME the creative subjects that are suffering. More and more schools are offering a smaller number of GCSEs, and I do see why, but the effect, coupled with focus on STEM and the now gone Ebacc, is that many DC have perhaps only one or two choices and subjects like drama, textiles, food, PE, art, DT are getting sadly sidelined. At least let’s have the students taking those subjects for three years; three years of breadth and variety.
And yes, my DC were all relieved to give up (variously) PE/DT/food/art/drama/music (tho all thankfully took at least one of those) after year 9. But there's a time for that, just as there is a time (post 16) to drop other subjects you might dislike (English and maths and biology for example).