I think good solution would be giving power to players because blizzard is simply not capable of dealing with botters on their own.
What i do mean by giving power to people? Introducing private servers where owners would be paying to blizzard every month. You would be paying based on number of online players.
Owner can use own modded game to run the server. It would work similary as minecraft realms. People could of course still play on classic basicly unmoderated servers as now but have option to play mods or normal actual version of game on private servers.
I think its interesting suggestion for blizzard as it can generate some money. It would be amazing for players because we could have our own sanctuary on servers not plagued by cheaters and play the game as it was intended to be played.
I think that majority of player base have no clue how much better is game play on clean server without cheaters. I had opportunity to play on few in my time of playing of D2 many years back. And my best memories are from these times, not from battle net. And i had opportunity to be in position of normal player and also owner of server like that.
Do people cheat on private servers? Yeah few lost souls tried to bot or use maphack/pickit and they were swiftly dealt with, deleted/banned because control on small server from mod team who actualy care is far better than on server managed by blizzard and their anticheat.
I think that D2R is in proper place to do something like that as we get less and less from blizzard team for d2r in term of content and also bot situation.
And hey, we could have our own special pvp server just for pvp with modified patch made for that.