Actually in conversions we usually use "个" , it's common used and an oral word. But "名" is more formal and sometimes it has a meaning of respect someone when it refer to introduce others.
For example, 1 "我只是个学生罢了" means I am just a student. (in conversion)
2 "Tom是个医生"
3 “Tom是名医生”
sentence 3 shows more respect than sentence 2 when introduce Tom.
In conclusion:
1、"个" is ok in conversion or some unformal articles
2、"名" shows more respect in oral expressions or articles
3、"名" is more formal and literal than "个"