Design of Class-AB output stage
Thumbs up - discretes-based audio amps used to be my favourite toy... Size doesn't matter, the fun comes from trying to understand how these things work. Looking back, this is where I cut my teeth on feedback control :-) Class D (PWM) takes all the analog fun out of the journey (but still leaves you with some mildly annoying analog side effects).
Speaking of class AB, there are hardly any simple solutions / low hanging fruits / shortcuts. If you use plain resistors to drive transistor bases in the output stage (common emitter followers), the power transistors will run out of base drive current just where it's needed most (close to the power rails). Constant current sources work better - they're stil not perfect though, because they do not pull all the way rail-to-rail...
If you'd like to see a more complex and proven class AB output stage (still not quite rail to rail), google DPA220. While now historical, in its day it was a fairly decent design all around. Namely, the adjustable biasing stage just before the output power totem contains two transistors that were thermocoupled to the main heatsink (if memory serves) to achieve negative dependency of quiescent current on temperature...