It sounds more like self induced heartache. Sure the loading times are slow for loading settings (got better over time) but shouldn't you have grown accustomed to checking the WiFi status on the gamepad before launching Smash after a few times of noticing it dropping your connection? I believe in the top left of the gamepad you can tell if you system is connected at menu screen (not sure if you can tell if you quick launch a game though).
Not really, because waking up the next day after sleeping only 2 hours because I played smash or mario kart all night wasn't really fun either.
Also, sure I got used to it after 2-3 times, but here and there after having not played for a while, I would forget. In 2016, you should be able to manage wifi on the fly while in game.
Another thing is that this kind of problem is one example that represents many other issues. It also reflects the time it takes to purchase and install DLC. What an annoying process. And shopping on the e-shop is a real pain. Slow and difficult to navigate.
I just was not at all a fan of the WiiU's OS.
The first part is odd. A connection loss shouldn't require a reboot. Anything else not regain connection while still powered on? The Wii U follows the 802.11 protocol and retransmits the association probe request at peridic intervals. Sounds like your router may not be sending disassociation and disathentication frames when your parental control timer kicks in thereby leaving the Wii U assuming it's still connected and therefore not sending out request probes again until you reboot or reset the Wi-Fi settings.
The second part is more an OS issue. Nintendo outsourced their integrated development environment to Green Hills Software and they did a very poor job of integrating it with the OS. Also, why in the world do you need to change your network settings in the middle of a Smash game?
You shouldn't usually have to, but in my use case I did.
To give you another possible example. If I take my wii to another place that has wifi (maybe a cottage or a friend's place, or I'm living somewhere else).
I load up smash and forgot to set up the Wifi settings. Well, I have to go through that tedious process again.
I'm not saying it's typical, but it's an example that reflects a wider lack of quality (which you supported with the outsourcing to Green Hills Software).