I sent both ticket and in game suggestion while posting on official Dk forum.
It is not the last build it will be plenty but removal of abilities do not happen for a reason.
It is not useless, better safe than sorry. Remember what we see in test realm are decided months before so live studio may be thinking about final touches of expansion by now, we should make haste if we want to change something.
Like every boss, Sindragosa was oversized in the raids due to the raid size and visibility issues. I agree she should be a little bit bigger and less Cd like Legendary legs for example, but ability itself is literal foundation of frost Dk. Frost quarter in ICC tells a clear story in this regard. I wish we had Arthas's animation from Heroes of the Storm including the channel time, that would have been godlike!