I agree, the best mod you could do is to buy a Wii (non mini, non Wiiu), and an OSSC - and call it a day.
Price of Both 160 USD inkl. shipping. Thats including two controllers, two wii motion plus, your choice of color, ... maybe add 30 USD on top for a shielded component cable, and 20 for a SD card. (And then 50 for a USB drive if you also would want to play Wii games from SD media (also buy a y cable.) ).
See:
https://gbatemp.net/threads/why-is-a-flash-drive-in-a-wii-softmod-not-good.594272/#post-9581439
Two positives - every emulator for the wii can output 240p, which the OSSC can scale 5x. (Thats the reason to go with a Wii instead of a WiiU - which has an HDMI out and wouldnt require the OSSC.)
See:
https://gbatemp.net/threads/tut-quick-240p-emulation-guide.589987/
Wii (or WiiU) can force most GC games to be played in 480p. (The main weakness of the OSSC is deinterlacing quality. So if you can feed it p (progressive) signals, you do.) Same for most Wii games.
That covers everything up to - but not including PS1 and DC for emulation. (Also not PS2, and not OG XBOX and later generations of course.). GCN and Wii through Nintendos native downwards compatibility.
With only two emulators on the wii installed.
Retroarch (for the exact version look into the 240p thread linked) and mGBA (official wii version). (Because the standalone version of mgba is faster than the core included in Retroarch and therefore doesnt stutter in demanding GBA games like Final Fantasy VI).
Three - if you are a fan of old adventures, because the Wii version of Scummvm can run all Scummvm games up to Bladerunner, and the Wii Motion plus input scheme actually is great on Scummvm standalone.
Also - there is PS1 emulation on the Wii - but its hit or miss. (Use different solutions for that).
Thats your entry into everything, if you are ok with emulation of older systems. Which by now is pretty darn good.
OSSC will scale 240p up to a very good quality 1080p signal (linedoubling), will allow you to play with scanline options (on the OSSC) which are quite good, and a few color adjustment settings - touched on in this thread:
https://gbatemp.net/threads/gbs-con...did-recently-and-think-it-is-worth-it.600330/
If you buy a XCM multi-console component cable, its also your entry point towards PS2, Xbox, and so on in the future, at no extra cost.
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Is the image as "pristine" and sharp as with a digital signal out? No - but its pretty darn close -
(you are looking at the OSSC example)
and the option to add (low intensity scanlines), and some blur (See 240p thread, GBS control thread, and this thread:
https://gbatemp.net/threads/tut-cheating-yourself-to-16-9-glory.590082/) imho is better, than having the cripest of signals - on pixel art games.
All newer systems are at 480p component signal quality, with a very good analog to digital converter (OSSC).
Only downside is, that the OSSC doesnt handle 480i that well (blurring and combing artifacts with bob deinterlacing, I usually use passthrough mode on the OSSC for 480i signals, and let my TVs scaler (decent enough) handle it.), and that you can fix for 45USD - see GBS control thread.
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So far you still only have 160USD spent. And a great image on your TV. (Look into the 240p and "cheating yourself to 16:9 glory on PS2" threads linked, example images are in there.).
And in terms of learning curve - well, you start by reading all the threads linked in here - and for Wii hacking, the only tool you need is ModMii:
https://gbatemp.net/threads/modmii-for-windows-official-support-topic.207126/
If you dont care about old game emulation on a Wii (you should, 240p 5x upscaled by the OSSC is the reason (with 'gradually adjustable' blur and scanlines)), go with a WiiU. Then you dont need the OSSC.