After 4.10 update I’ve finally considered to make this post.
Download manager in launcher is very ineffective (but fast)
This is KiteDemo comparison table, each folder is about 24.8Gb in size, 13.3Gb are different from folder to folder.
It’s 11.5Gb of same content per each version. AFAIK, traffic from amazon s3 ain’t free, i.e. 1000 downloads will cost You additional ~$300 (100011,5Gb0.0275$/Gb) for only one asset (largest, but still). Plus, not all the users have a 100M Internet connection.
If You just implement even a basic script that will copy (or move, personally I don’t need 25x3=75Gb of project files) files from existing project based on diff table (it is permanent!), it will save YOUR money (ofc in case it’s not implemented yet).
p.s.: also please consider to add a BitTorrent protocol, that may save You much more (some AAA publishers using one in their launchers)