Because of the things blizzard is doing this move is needed to help stave of some serious issue that can arise with RMT. I think they are bold for doing this and it makes sense why they would. In this iteration of the series SP has taken a backseat, especially given the popularity of MP in D2.
No, it doesn't make sense. I can respect the desire to avoid cheating and to emphasize solid MP gameplay. But from a technical perspective, how hard would it be to give you a choice of local or server storage for your character at the beginning of a single player game? If you choose server storage, you need an Internet connection and you can use that character in online games. If you choose local storage, no connection required but that character can only be used for single-player games.
If you don't like it, don't buy it. It is not aimed at those who have trouble with the internet. Your troubles with the internet does not supersede the design and direction of the game.
Of course I have the option of not buying it. I also have the option of bitching about a stupid requirement to play a game. My bitching is not aimed at players who see no problem with the requirement. It's aimed at Blizzard, to let them know why I won't be a customer for this game. Your irritation with my bitching doesn't supersede my right to bitch or to let Blizzard know that they have potential customers who are not actual customers because of this decision. If you don't like my bitching, don't read/listen to it.
For what it's worth, my perspective is influenced by serving twenty years in the US Navy. When you're stuck for six months on a ship at sea with no personal Internet connection possible, games become a great way to pass the time. As more and more games make an Internet connection a requirement for playing even single player games, it'll soon get to the point where you aren't choosing to not purchase a particular game but are being forced to give up gaming entirely.