It would be great if the team information would be removed from a user when they are inactive. I did some tests and it doesn't look like historical data is messed up with the remove of the person from the team.
Would need to ensure that reporting based on year to date or last year would still include the removed users efforts.
For example, if you have someone on your team that leaves the company in October, and you run Q3 numbers that person's assignments and hours still need to be included in the totals.