Don't be fooled by thinking disc brakes are 'needed' on the rear of a light (nose heavy) FWD car, they aren't - drums are perfectly satisfactory (and actually more effective than discs because they 'self servo'). If there is any criticism with the brakes on my TA, it's that they might fade after repeated high speed braking because the discs on the front are solid.
You left out the proportioning valve. Because a disc/drum system is essentially a mechanical miss match, the proportioning valve delays releasing pressure to the front discs, until sufficient pressure for the drums has been reached. It's only a fraction of a second, but it's why rear disc cars feel better under brakes.
The 'self servo' effect is also a problem as it actually needs to be engineered out to stop the rear brakes locking past a certain pressure. EBD helps no doubt, but is really masking the real issue. In many ways, it's better to start out with a balanced system, especially if people are thinking of adding bigger discs/ calipers to the front.
But I agree, bigger discs will make the braking system 'feel' better/ more powerful, but actual braking power on the street (where fade shouldn't be an issue) is really down to vehicle mass vs traction, as long as the brakes are strong enough to lock the wheels, it doesn't matter if they're big, small, vented disc, drum, single or multi pot. In fact, in a freeway emergency stop with stone cold brakes, smaller brakes will reach temperature quicker and might out perform a set of Brembos.
I plan on getting a tuning box, but am probably going to keep the braking system stock. The best way to keep these little engines (and brakes) happy is to keep the car light.