Similar things have been suggested previously. That game already generates the number of international appearances and goals if you specify a manager that starts with international experience. But it would be great if a career history was generated fro every manager based on experience level, place of birth and career templates covering a range of careers from one club to multi-country journeyman. Would definitely help in giving your manager a story and help determine what clubs you might want to manage (or avoid).
Would also look better in your biography if it included a playing career (and maybe if you chose an older starting age for your manager, a coaching career as well)