Wow so long for new sisters? That is quite unexpected for me. I thought that new codex in WD is just begining for new models. But on the other hand I will rather wait 2 years if new codex will be excellent.
Even though I play SM I dont like much that most famous chapters has it's own codices, though I understand the concept of it. Because of this BT and DA are now one of the oldest and unplayable :/ If even CSM legions will have their own...well..that's quite bad.
But it is all about more money, isn't it? More codices, more models, more £
But If you wrote to GW some suggestions about new Sisters codex, lets pray for the Emperor that yours and other players wishes come true