I think the Digital Ocean platform would be a lot more attractive to high traffic architectures if the sum of all droplet-transfer could be added up to a total. Where this total transfer is consumed shouldn't matter.
Say for example I have a high traffic site that needs 8 webserver droplets of 1GB that serve the webpages (internally). An in front of those I'd need a load balancer droplet of 1GB that distributes the incoming requests over the webserver droplets.
So all public traffic goes through the load balancer droplet, all communication from and to webservers is internal traffic and doesn't count towards the cap.
Now my total public the website can serve is 2TB (since the cap of the load balancer is the only one useable). While my webservers could easily handle the needed 15TB for running my website.
The current droplet models would not even allow me to use Digital Ocean since the maximum cap is 9TB, and paying for this unneededly big machine plus the 6TB extra traffic is unattractive.
Alternative would be to us DNS load balancing but that is undesirable because of the inflexibility and dependence on how clients handle receiving multiple IPs for a name.
How would you architect a high traffic website on Digital Ocean? Maybe I'm just overlooking some options :-)