You're not. I grew up coddled up to my sweet, sweet SNES (My mom taught me how to read using FF4, which started my addiction to RPGS), and I've been disappointed since the Wii/DS era. I enjoyed the N64 (even with some of their design/hardware choices), and I loved the Gamecube (really felt ahead of it's time in ways).
Sure there are some pretty good games for both systems here and there, but this was pretty much the point where Nintendo began dishing out controller gimmicks over gameplay. I've seen very few games outside of first party titles for the wii that make an actual innovative control scheme that wasn't "flail your arms and do jerking-off motions to win!" I kid you not, I've actually done this in multiple games and began tearing things apart, which admitedly I find hilarious in ways. Though to be fair, one game actually uses that as a real control mechanic (No More Heroes) which is one of the few non-first party titles I could play for more than 10 minutes.
The DS, on the otherhand, is for the most part pretty enjoyable. Definitely better gaming options compared to the wii (and for the most part, the Sony PSP, it's competition for it's time). It still felt like it was just a GBA with more screens and buttons, but at least the games generally made better use of its control gimmicks, minus the games that FORCED them with no alternative schemes or basic button controls (like those god-awful Zelda titles and Star Fox).
Now they focus on that AND try to put touch screens into every orrifice they can. Not to mention they (once again) gave themselves limitations that drove off a fair amount of 3rd party support, starting with the Wii and continuing into the Wii U.
3DS on the other hand, reminds me of a little handheld Gamecube with some of the stuff I've seen. If I could find one for a decent price at a pawn shop I'd have a field day with some of it's library.
But all of that is just my personal opinion, and how I feel about Nintendo these days.
As far as Let's Plays and Youtube videos go, I'm quite neutral about 'em. I'm not really into watching someone play a game if I'm not sitting in the room with them, but as other people said they are a good way of seeing a game in action outside of a review or gameplay trailer.