I just wanted to chime in and provide a bit of context around this issue, and an update on our plans for it.
The current behavior of the Improved Weapon Totems talent actually does match 1.12 and the reference client, and this talent behaved in this way for its entire existence during original World of Warcraft. It was, however, recorded as a bug shortly after it was introduced late in 2006 and was fixed very early in Burning Crusade. Since this is a clear bug that was fixed relatively quickly in the original game, we do currently have plans to fix this (as well as several other issues that were similarly bugged in original WoW but were clearly incorrect behavior) in an update coming in the near future.
Hang in there, enhancement shamans!