Our SOPs require that the A/T are never fully disconnected. Yes, we do take out the autopilot, and announce it to the other chap, and also ask the other seat for "Speed Off" which requires speed to be deselected on the MCP. Following these actions, an alarm sounds for the AP disconnect, and the red-flashing warning light for A/T flashes. The Speed Mode is then shown as ARM. In these circumstances, thrust will return automatically when the actual speed falls below the selected MCP speed.
However, in the scenario where Vertical Speed is armed, the speed window opens at the selected speed, and the aircraft will attempt to match the specified vertical profile. One can place a lower altitude in the window to arm V/S, or as would make sense in this scenario, the missed approach altitude can be selected, and a vertical speed initiated - now there is no floor to prevent the aircraft acquiring an altitude which can mess everything up in a ILS! We've all done it, when everything is looking dandy, suddenly the ALT ACQUIRE pops up and the descent/re-capture close to being ruined. Fancy handy work, normally by quick hands on the MCP, or manual flight is really the only option then.
Vertical Speed offers absolutely no speed control. Although the autopilot is flying, it concentrates only on obtaining the nominated V/S, ignoring the speed entirely.