That might actually be a sensible idea, Pooh; one or two days a week that's guided in that sense. Compromises are often good. And of course, you don't want a child to be always unhappy or lonely.
At the same time, I think there is a risk that the OP may actually be adding to her ds's upset, by treating everything that upsets him as very serious. (I didn't actually mind too much, being lonely in the playground, but I am sure if my Mum had commented on it and seemed sad, it would have made me feel I was a failure).
The playground business is understandable: it is heartbreaking when your child seems lonely.
When it comes to minor issues of discipline, though, I am really not sure you are helping your ds by encouraging him to feel put upon. If the teacher did not blame him for something he hadn't done, but merely moved him (and others) for matters of expedience, then I really don't think he should be encouraged to make a fuss about it.
I used to run a 3-tier system when my dcs were younger (in fact, I still do with my teenager):
For most daily upsets, I would listen sympathetically and nod my head sagely: "yes, I can see that would be very annoying, dear"
For issues that were slightly more borderline, I would say:
"yes, I can see your point. What do you think we should do? Should I take it up with the school or should we leave it?"
and most often they would say leave it, but feel reassured that if they really did want me to act, I would
And then there would be really serious issues of out-and-out bullying or discrimination or safety issues that really needed dealing with- and with those I would deal regardless of dcs' take on the matter.