Zelda games average 4m on console so its hard to say, Zelda U is the most anticipated game on the platform Nintendo has a high attach rate so I'm still unsure if anything on Wii U will shift it outside of Smash and MK as I can see it doing 5m LT.

I'm talking about on future consoles tho not the Wii U

Ahhh, then yes Splatoon will outsell it on future consoles, I can see the series hitting the numbers a series like Animal Crossing and MK normally tough.

It is far more accessible than Zelda, that's for sure. People like games where they can connect with a community and interact, and Splatoon is the epitome of Nintendo online gaming.

First Zelda and Metroid don't have nearly same importance of popularity for community or Nintendo. Second even Zelda dont have huge sales like Mario, Mario Kart, Smash Bros and now and in future like Splatoon, evre 3D Zelda is always one of the biggest and most important projects/games for Nintendo evre generation.

If you're talking about Zelda Wii U, then Yes! Splatoon will sell more than that one.

Will Splatoon sell more than all the mainline Zeldas on the WiiU (WindWaker HD + Twilight Princess HD + ZeldaU)? It might be a tight race, specially when we don't know how many Zelda U sales will go to the NX, if it goes at all.

I think that in a few years, Nintendo's highest selling franchise, per release (and type of game), will go as follows:
1. Pokemon (main series)
2. Mario Kart
3. Splatoon
4. 2D Super Mario
5. Super Smash Bros.
6. Animal Crossing (main series)
7. 3D Super Mario
8. Tomodachi series
9. 3D Legend of Zelda
10. 2D Legend of Zelda
Honorable mentions: Fire Emblem, Luigi's Mansion (if they make it a recurring series), and Donkey Kong
*This is assuming that NX is a hybrid console/handheld system.

Hell, we don't even have to wait Splatoon 2; the first game is already on track to outsell every Zelda game since Twilight Princess a decade ago. I wouldn't be surprised if outsells Zelda U as well.

I think Zelda U can sell better. In fact, I think it can sell close to MK8 numbers.

I'm also delusional about Zelda. I'm not lying, though. I think Zelda U will outsell Splatoon. I just don't think it's based on any sound logic.