The Switch successor will be the first gen 10 console. Wii U and Switch don't belong to the same generation, because Switch is Wii U's successor.

The third generation was also only 4 years long (1983 - 1987) and we haven't seen a successor from the same company which belongs to the same generation in the whole history of consoles. Not even Sega Saturn and Dreamcast belong to the same generation, although Saturn's life span was even shorter than the one of Wii U.

It's a bit unlucky though that Wii U was released one year before PS4 / Xbox One and got replaced that fast.

If I were to keep my opinion with the one I had in the past for such a debate, I'd prolly call it as it was to me, the 8.5 Generation. Categorized by the release of more powerful hardware by all manufacturers with the PS4 Pro, Xbone X and the Switch.

But now, historically, the Switch will have spent much more of it's lifetime with the lastest generation of console and it's successor is about to probably release in what seems to be the later half of the 9th Generation which will also possibly provide a new PS5 Pro model to boot.

For internal consistency, I'll call this the 9.5th Gen haha !
Nonetheless, it is clear the Switch will pass a major portion possibly against its 10th Gen opposition.

Conclusion, the current categorization of console hardware is flawed

 Check my post on page 1 for the Dreamcast, and Neo Geo. I didn’t put down the Jaguar nor the 3DO. I’ll post a full complete list later.

Agreed.

Ok then should there be a new one? And how will it be done?

I'm certainly not the one who's gonna make the claim for a universal answer on this debate haha but nonetheless, my use of .5 generations does a good patchwork imo.

Otherwise, people will just have to live with the fact that a console can be categorized to be part of two generations as the Switch lead to this debate in the first place. Either one or the other, or even both 

Much like genres I think generations kind of don't exist anymore.  Generations were marked, in a large degree, but exclusive games.  Ps1 was FF7, ps2 was FFX, etc.  

But with game engines being scalable and multiplatform....  I'm not sure what a generation is anymore. 

Visual output for the S2 will be roughly 8 gen, but it is also mobile.  

There are no new generations after PS2, GCN and Xbox.

There basically has been no progress in games in regard to gameplay mechanics since then, maybe with the exception for Wii but the gaming industry more or less reverted back to PS2, GCN and Xbox era in regards to gameplay after that.

Shiny graphics and slightly bigger open worlds does not define generation. Evolution of game mechanics enabled by new hardware features does.

It would make it the third generation hybrid.

The WiiU was the first hybrid console that could play games dynamically across multiple different displays. (Built in mobile display and fixed TV).
It was range limited, but that is what makes it a first-generation attempt.

LUNAR

1st console generation:
2 colours.
Single screen.

2nd console generation:
Cartridges for games.
8-bit Microprocessors adopted.
Colour and Audio.

3rd console generation:
8-bit microprocessors retained.
More sprites.
Ability to save games.
Improved audio with a greater range of audio effects.

4th console generation:
16-bit microprocessors adopted.
Parallax scrolling.
Wavetable/FM Audio synthesis.
Rotating/scaling of sprites.
Flat shaded 3D polygons.

5th console generation:
32-bit and 64-bit microprocessors adopted.
3D Polygon graphics with texture mapping.
Full Motion Video.

6th console generation:
32-bit and 64-bit processors retained.
Internet connectivity.
24-bit/32-bit colour.
TnL.
Bump Mapping/Hardware displacement mapping.
Shader Model 1.4/TEV/Fixed Function or equivalent.

7th console generation:
32-bit and 64-bit processors retained.
Broaband internet connectivity.
Hard drives for storage.
Programmable pixel and vertex shaders.
Parallax mapping.
Shader Model 3.0

8th console generation:
32-bit and 64-bit processors retained.
Tessellation.
Geometry Shader.
Direct Compute.
Shader Model 5.0
Dynamic resolution scaling/frame reconstruction.

9th console generation:
64-bit processors only.
Variable Rate Shading.
Hardware-based Ray Tracing.
Temporal reconstruction and anti-aliasing.
Mesh Shaders.