Well, technically Smash Bros for Switch would be just that, for Switch. Built of the same engine as the Wii U and 3DS version, but different enough (hopefully) to warrant another purchase.

I personally would like to see one built from the ground up for Switch, or even a version that literally has N64 graphics and sounds to have a retro feel to it. But building one from the ground up would take years.

Mario Kart, that game probably wouldn't take as long to develop so seeing an MK9 wouldn't be impossible. Though if that's the case we have to assume that it's in development already (MK9) based on the Switch reveal video. A Mario Kart 9 or I'm predicting it'll be called Mario Kart Switch (based on the fact that you can hold two items and switch them) would be desirable, and fresh because Mario Kart 8 is out and let's be honest, people want a new game, not a port.

My opinion. Any thoughts?

Yeah, I could see them pull both.  They'll just need to make it clear they are doing both early on.  If people suspect the ports are replacements for sequels, that will really deflate the hype.  

I don't know if we'lll see a 2D Zelda.  Link Between Worlds was successful, but not as big as the mainline entries.  It will be interesting to see what handheld oriented games stick around and maintain that handheld orientation and which ones become more console-ish.  On one hand, handheld style and scale experiences are cheaper to make even with HD visuals accounted for and can be sold at lower prices and thus slot into months that are too dry or too competitive for a 60 game.  On the other hand, if Nintendo's marketing maintains its current tone, most early customers will be buying the Switch for full on console experiences, so the potential of handheld experiences there is a bit questionable.  Also, it's clear that Nintendo isn't dropping the 3DS just yet, so there's also a question of when we'll see the full on fusion/unified library come to fruition.

Having two Mario Kart, Smash Bros and Splatoon games on one console is totally different than having two 3D Mario's, two 3D Zeldas, etc, beacuse MK, Smash and Splatoo are compettive online and multiplayer games and they were always (expect Splatoon offcourse) one game per console compared to basically all other Nintendo franchises and games.

We could have Mario Kart 8.5 and Diddy Kong Racing for instance instead of having two Mario Karts games on one console, Smash Bros 4.5 and remaster of Pokken Tournament, Splatoon is only year and half old game so Switch could easily get only Splatoon 1.5.

This is news to me. I just checked and it seems they co-developed a 3DS version alongside another team but didn't have involvement in the Wii U.

Given that they're taking (in my opinion) the best versions of Smash and Kart as their basis for the Switch versions, and given this means we get two of the staple Nintendo titles early on in Switch's lifespan, I'd be ok with it. The benefit of Nintendo unifying their development teams--and porting completed Wii U titles and moving over unreleased Wii U projects--should mean that we get a wider variety of Nintendo titles on the system. I'm all in favour of that.

I'd prefer to see Smash and Kart as service type games anyway, where you get the core experience on the console and updates every 6 months or year. For me they're essential games on Nintendo hardware, and are guaranteed hundreds of hours of local multiplayer.

The DLC alone would justify it being released as a new game. if they make mario kart 8 for the switch it'll either be all the DLC included only, or they may add an additional 4 grand prixes to make it a whopping total of 16 total.

Then it'd be a shame.

I'm almost certain the games will be enhanced ports from the Wii U version, with some extras added. The footage of MK in the reveal video looked like MK8.

Both of these games aren't that old and I think Nintendo will at least use their assets. The Switch will have more games coming faster than Wii U because of all the ports like MK, Smash, Splatoon, probably Mario Maker and Pokken Tournament too. That's 5 games.

I actually doubt Mario Maker will come to the Switch.  In fact, I think that's the main reason it is coming to the 3DS.  The Switch lacks the dual screen aspect that makes Mario Maker so convenient.  It would be a rather clumsy, inferior version if brought to the Switch.

Pokken I can definitely see getting a port with all the new Arcade content in there.  And of all the proposed port, this is the only one I am legitimately looking forward to seeing because even modest estimates put the Switch at a level of power well above the Wii U's capabilities and that would allow Pokken to look much more like the arcade version.  And since the DLC isn't already on the Wii U, I won't be rebuying all of that along with the game.  

The one I am least looking forward to is Smash.  Cause of all these games mentioned, it's the second most obviously held back by hardware limitations.  It looks nice, but far from what it could look like liberated from the Wii U (and the 3DS since we all know that probably impacted the visuals acrosss the board).  by all means, keep the big 3rd party characters this time rather than scrapping them (I think the historic ones like Cloud, Sonic, Megaman, and Pac-Man fit in really well anyway), but I really, REALLY hope we get a new one that pushes the visuals further, especialy with regards to the stages cause there are several on the Wii U version that just look like slightly polished up GameCube assets.

Agree, I also don't see Mario Maker being porting on Switch.