It is a server problem since the server does not support ordered relationships. Linking each part to the next part is just a hack - it doesn't work when some parts are missing (e.g. if parts 3 and 19 are in the database, we should be able to say that part 3 comes before part 19 even though part 19 is not the next part after 3) which requires twice as many relationships to be entered. It's also not just a problem for the parts relationship, other things like medleys and DJ-mixes should be ordered too.
There's no need for multiple tickets trying to solve the same problem.
MBS-3375doesn't say anything about implementing it with sort names and actually proposes an attribute on the relationship. If you think the description isn't clear enough, ask someone to improve the bits you don't understand.