The only game that I can see really being effected is 1-2 Switch (because of IR camera and needing to have the Joy-Cons separate in order to play). The Switch tablet itself has gyro and accelerometer inside so when the system is in portable mode it does not use the motion controls inside the Joy-Cons (and I imagine a Switch Mini would also have it built-in); the motion controls in Joy-Cons are only really used when they are detached from the system. As for 1-2 Switch and games like it, players will have to purchase Joy-Cons separately. If a Switch Mini ever comes to pass like how I described it, I can even see Nintendo bundling certain games, like 1-2 Switch or maybe even ARMS (even though that can be played without motion) with Joy-Cons in order to get players to purchase them. A worst issue would be Switch TV would not be able to play games that need a touchscreen (like Voez). I know this sounds less than ideal but this is not the first time we have seen games break compatibility after a revision. In fact, worse cases than that were with DSi which lost the ability to play DS games that needed the GBA slot; PSP Go which could not play any physical PSP game; Wii mini which could not play games that needed to use USB peripherals nor could it play any of the Virtual Console or WiiWare games because it had no Wi-Fi. 

Also, I envision the Mini revision will come around whenever Nintendo launches the new Pokemon game (I assume 2019). I can see it being around $200 in order to entice kids and, more importantly parents; this is also the point where I think households with multiple children might start purchasing multiple Switch's for their kids. I suspect the XL version will launch earlier if it does not contain spec updates (like New 3DS did) or later if it does. The XL version will cost the same as the existing Switch model does at the time at which it launches (if the Switch is $250 by the time the XL launches then that will also be the price of the XL). The XL model would essentially replace the current Switch and the Mini and Switch TV would be less expensive alternatives (the Mini would also indirectly succeed 3DS because it would be targeted towards the younger crowd that the 3DS is going after now).

Sorry if I sound silly but is there not measures Nintendo and other devs can implement to reduce the chances of screen burn in menus and games?

I know if you play F Zero on a hacked 3DS using rom injection it can burn the map into the screen while other roms don't do this and there was fixes implemented to stop it from happening.

A cheaper version

A better battery life, more internal storage space and a revised dock that does not scratch the screen .

One thing above the rest: Glass capacitive screen.

And OLED.
With small bezels.

Joy-con with good D-pad. Wii Remote compatibility.

I am genuinely amazed that nobody else seems to mention ergonomy. Because that is the main reason I haven't bought the Switch: Playing in handheld mode is extremely crampy for me thanks to the joy-cons. They offer no grip for above average sized hands, the buttons are too small and the layout of the right stick makes it almost impossible to play shooters like Splatoon 2 properly.

I wouldn't even need a complete revision of the console, just a modified set of joy-cons might be enough. However, as the 3DS has extremely bad ergonomy, too, I doubt that Nintendo is aware of or cares about the issue.

Handheld have ALWAYS sacrificed comfort for portability. Whats the point of being portable if its cumbersome? Handhelds need to keep a flat profile.

Honestly the switch is a HUGE step up from the ds/3ds in this and even managed to surpass the GBA in this reguard. And plus you can always use the included grip or a pro controller 

Revisions are pretty much essential if Switch wants to reach the 100 million mark IMO; they're a huge part of why previous Nintendo handhelds sold as well as they did. It makes the product seem new and fresh again, while appealing to those who may not have bought the original design.