It does seem unfair sometimes how the League draw works out. Especially so when you are grouped with much stronger (usually tanking or token buyers) This has a lot to do with how strong your team is at the end of the season. If you keep your team under 100% on the final day of the season you will be grouped with weaker teams for the next one. The League draw occurs on the server maintenance on Season Day 1 although you do not see it until Day 3.