One of the major things they did wrong was they forced all WC3 players who did not even buy Reforged, to download a 25gb patch to upgrade their client. This 25gb patch actually removed a lot of features such as LAN, custom campaign, win/loss stats, arranged teams, etc.
They should have just let classic players stay on ROC/TFT as separate clients and not jumble them up into this mess.
Here is me playing the game for the first time and reacting to it: