StarEye: The fact that you consider the replies to your post 'flaming' backs up my point perfectly by itself, so there's no need to reply in detail anymore. I'd just like to add that there is no
'objective judgement' (as in: it doesn't exist). So what else do you expect then subjective views being used as arguments? Also, I strongly disagree with your definition of 'overrated', as it again implies there is some 'common truth' as defined by 'predominent opinion'.
Burseg: I disagree with your disagreement
There was 'mainstream' in the days of the Amiga just like there is today. The difference between mainstream and non-mainstream has just become larger. As for your point about computers themselves not being 'mainstream', that's no problem. We'll just have to define the group of computer users as the 100% to base all of our numbers on, and every common definition works again
So, to get to the point, I'd define 'mainstream' as anything corporately produced which most people of the target audience (Amiga/computer users) liked. Take Lucasfilm/Lucas Arts Adventures or games like Dune 2 - that's mainstream. What's not mainstream? Anything produced by some 'bedroom programmer', anything largely overlooked by the (computer) public.