The adapter is annoying in that it obviously continues to consume power even when it is switched off. This can be particularly annoying if you are trying to minimize energy consumption. Even if the temperature difference, as with your L30 II, is only 20.6 °C above the ambient temperature, the constant flow of current is an inefficient aspect. Especially with devices that are switched off regularly, you would not normally expect any noticeable energy consumption.
I just measured the adaptor with no load (E30 II in the "off" position), and it takes 1.7W. I'm going to measure its temperature above ambient after sitting for an hour -my guess, it'll be 2, maybe 3C above ambient (at its hottest).
Now, 1.7W isn't nothing, but it's hardly something to worry about. If you buy the L30 II and plug it in and leave it plugged in 24/7/365/5, at the end of those 5 years, the cost to you was less than 1 dollar.
Yes it would have been better if the power switch was in line with the primary side of the transformer instead of the end of the wire from the secondary, but in order for that to have been the case, for the switch to be in the L30 II, there'd have to be an extra conductor in the power cord (requiring a non-standard power cable), and then there'd be dirty dirty mains voltage inside the device itself which would probably necessarily be horrible for SNR unless the case was made to be sizably bigger (+30% at least...) to accommodate shielding
Any remedy for this switch problem isn't cost effective to fix. Bigger chassis? No for so many reasons. Extra wire? Costly and requires bigger chassis
Think about it like this: that 1.7W is the equivalent of your TV's brightness set to 12/30 instead of 11/30. That 1.7W is like the gas to heat the water for one shower. That 1.7W is like your router manufacturer using an Intel chipset instead of Realtek for the LAN. That 1.7W is like cooking a 1.25 pound lasagna in your toaster oven at 350 for 40 minutes. In other words, it means nothing.
Maybe think about it like this: Topping could've put the switch on the wall adapter itself... Would you buy the L30 II with the switch on the wall adapter for $149, or would you buy the L30 II with the switch on the unit for $150?
There's a technical term for this kind of power usage: "phantom power draw"
You can work to minimize it by using power bars wherever you can and shutting them off when you're done, or, say you have an office, you can do the electrical so that the bottom outlet is on a wall switch - plug your power bars into the lower outlets and when you leave, turn off the switch. There are things that take power that you'd think wouldn't when they're off - my Denon X3700H takes almost the same as the E30 II - its USB port is always powered up, HDMI has to be in standby for power-on signals, the thing has WiFi for streaming...
Basically, I think you should be less annoyed because it's a small power draw. I probably wrote more words than necessary xD