From a network standpoint:
Packet loss if affected by a wide factor if I am in New York and the servers are in Seattle a wide trip would have to be made.
I rarely get packet loss but my neighbor across the street from me gets a green-yellow bar and he has a different ISP but his internet is faster than me (1 GB/s) I only have 80 MB/s Download and 90 MB/s Upload
Quoting from /u/JWILL522
This is it right here. This is why you should never take Destiny seriously as a "competitive shooter". It simply can't keep up.
This is especially correct. Destiny is never a competitive shooter. I can watch my K/D all I want but it is still not competitive. We can say it is but it still isn't. I can make a competitive game and have my friends play and that might be "competitive" but in all reality is isn't.