Ok i just tried it and i have to say that it doesnt feel better. The only benefit i noticed is when i clear
the wave based echos that iam way more mana efficient because most are trash mobs.
In normal runs i still deal same or more damage with chakrams.
Also you were right the single target dps AND mana management changes. Before i could just Shift -> Sync Strike or Sync Strike -> Shift. That limits my repositioning in boss fights which i dont like. And the maybe more important part is that i always can chakram after Sync Striker because of the 0 mana affix but shift doesnt work then.
So i stick with your variation. 🙂