In general, Amazon Web Services and other cloud services get blocked on Wikipedia and other wikis. (This is because they have traditionally been used by spammers, and there have been few to no legitimate edits coming from them.)
In addition, multiple Tool Labs tools can get blocked when an admin tries to block a single user or tool.
This means that legitimate OAuth apps that make edits can't be run on AWS (including Heroku, which was the platform my team was developing our app on before we ran into this problem). Perhaps approved OAuth apps (or some subset that have limited potential for abuse) could make edits with already-existing user accounts even from blocked IPs?