[Kleiner]

SR will cast drain when missing more than rough 1/5th of its HP. Essentially, if it gets hit at all, it's gonna cast drain. However, DRKs don't gear for usper M.ACC or anything and they still manage to land solid Drain IIs. Assuming Drain II on SR followed the same cast requirements as current Drain I, having it upgrade the spell would at least be better than just having Drain I. Like every other PUP out there id' rather the spell go away, but SE isn't gonna do that.

[Alkar]

You'll probably be able to pull Tactical Switch off without Retrieve. Honestly I've never noticed the "several seconds of cooldown" after a WS as I can cast a spell or use a maneuver right after a Pummel. Puppets don't fire their WS right away, there should be more than enough time to use the ability.

[Suljin]

Generally you can use ja/spells just before the final swing in pummel, its a good time to get a last maneuver in before the auto ws after if you have inhibitor up.