it seems that both of you were spot on!
well, graydon let's be honest that S shaped trunk is so mall-sai and unnatural that we all hate it. But I didnt when I bought it like one year ago because I knew practically nothing about bonsai (I even thought that bonsai are like sub-genres of trees that don't grow a lot!!!

) Well, now of course I have studied a lot of articles and it didn't take me long to understand that the trunk is not good.
Buying another bonsai to divert my attention is among my thoughts for months now but unfortunately there are absolutely no bonsai nurseries like 500km near where i live! I'll probably have to find one good specimen from nature.
back to the topic now, two questions.
1. I'm kinda afraid pf leaving the same branch structure for a long time, i think that the trunk it's gonna grow assymetrically. I thought pruning back some branches and let some other ones to grow (like sacrifice branches) will make my trunk grow in girth more symmetrically. For example I had this big branch on top, and when i chopped it I realised that the trunk's shape was heavily distorted, it wasn't circular but oval!
2.How about a trunk chop that will help me to straighten out the trunk? (and give some taper of course) Would you suggest it? I guess it's a very "slow" but efficient way to achieve taper. When and where should it happen? Would it be possible to airlayer that aswell and then have like 2 trees?
and PS
anyone know a website shipping around europe nursery (not ready - for training) material

That would help a lot. Focusing on one plant while changes occur slowly isn't a good thing for sure.