It's all subjective opinion. But asking my subjective opinion, the answer is: no, it wasn't.
You can certainly argue the the GC controller was better than the Wiimote/Nunchuck setup. However, with the Wii, you had the option for a GC/Wavebird, a Classic Controller (or later pro version), Wiimote/Nunchuck, AND arguably the best, Wiimote NES style. You had plenty of controller options, and that was nice.
Gamecube had some great games, like Smash Bros. Melee, Metroid Prime, Pikmin, Chibi Robo, and Twilight Princess. But to ME at least, it also had many games that were serious missteps for their franchises, and simply not at all what I wanted or expected from them, such as: Super Mario Sunshine, Zelda: Wind Waker, Mario Kart Double Dash, and easily the worst offender, THE single biggest gaming disappointment in my life, something I initially got hyped for until I played it and realized it was a steaming pile of aborted fetuses, Star Fox: Assault.
By comparison, for all of the rampant talk (then AND now) about how Wii was just a "casual" console, and Nintendo was "abandoning the core gamer", the fact is that was never at any point actually true. In reality, the Wii got me personally, back into gaming more, after fading out on it a tad in the GC/PS2 generation. By comparison, the Wii actually had a TON of great games available, both on retail disc, as well as digitally through the VC and WiiWare services.
By comparison, and don't think there even IS much of a comparison to be made. Gamecube had several great games for it. But Wii had, I think it's pretty easy to say, far more. These included but were not limited to:
Wii Sports, Excite Truck, Super Paper Mario, Metroid Prime 3/Trilogy, Fire Emblem, Battalion Wars II, Super Mario Galaxy, Mario Kart Wii, Smash Bros. Brawl, Geometry Wars: Galaxies, No More Heroes 1 & 2, Zak & Wiki, Trauma Team, de Blob, Wario Land: Shake It, Mushroom Men, New Super Mario Bros. Wii, the RE Chronicles games, Muramasa: The Demon Blade, the Okami port, the superior RE4 port, Boom Blox, Fragile Dreams, Ruin Factory Frontier, Kirby's Epic Yarn, MadWorld, Endless Ocean 1 & 2, Sin & Punishment 2 (and finally getting S&P1 on VC), Punch Out, Kirby Return to Dreamland, Super Mario Galaxy 2, Red Steel 2, The Munchables, The Conduit (first one was decent), DKCR, Silent Hill: Shattered Memories, Cursed Mountain, the Klonoa remake, Mario Strikers Charged, Monster Hunter Tri, Cave Story, Final Fantasy IV: The After Years, Lost Winds 1 & 2, Blaster Master Overdrive, La-Mulana, the Konami Rebirth games, the A Boy and His Blob remake, Mario Party 9 (the best one since N64), Little King's Story, Fluidity, Tatsunoko vs. Capcom, Tetris Party, Dr. Mario RX, the Bit.Trip series, Rhythm Heaven Fever, the Art Style games, Xenoblade Chronicles, Zelda: Skyward Sword, The Last Story, Pandora's Tower, etc.
And there were also the other Japanese VC games we finally got, like SMB2 (Famicom version), Castlevania: Rondo of Blood, Monster World VI for Genesis/Megadrive, and the aforementioned Sin & Punishment.
Like I said, it's all subjective opinion. People who think GC is better, or that's their favorite console, have every right to feel that way. But in spite of it's flaws, and in spite of the rep it unfairly seems to have, you can plainly see that Wii actually had a strong wealth of games for it, both first and third party. The sheer disparity of such, in fact, compared to Wii U, is astounding when you really look at it, and I didn't even list all the games I could have, as there were many more quality exclusives and ports that could be mentioned.
And as such, the tired "Nintendo abandoned the casuals with Wii" meme is obviously disproven. They alone released FAR more "core" titles than "casual" during that gen...on Wii AND DS. So that debate has always been a dead-end by dumb fanboys. Just saying.
I certainly wouldn't call Wii my fav. console of all time. Not even close (that'd be NES and SNES). But it was a good console with a lot of really good games on it.