I don't own a WiiU so I can't say anything about MK8, but I bought a Wii last week and I had a similar thought after comparing MK:Wii with Double Dash of the GC.

Double Dash is far better and more addicting than MK:Wii for me. The same applies to SMB, Melee is so MUCH better than Brawl.

I had fun with MKWii, but found it my least enjoyed game in the series. It became too much about luck, rubber-banding and punishing whoever is in first place. Blue shells were not only too common, but didn't travel along the ground, so they only affected 1st place and whoever happened to be nearby when that person got nuked. 8-12 were always guaranteed awesome items, while 1-4 were guaranteed crap. The skill factor of the game became less about staying in or around the lead, and more about making sure you're in the right place holding the right items once Lap 3 rolled around. I can see how that can be fun for some people, but it's not for me. And I'm not even going to get started on bikes or the difference between light and heavy racers.

Mario Kart 8 went a long way toward fixing most of that. Now I don't have to purposefully hang out in 2nd or 3rd for half the race to avoid blue shell rape, or limit myself strictly to bikes and heavies to hope to be somewhat competitive (not that heavies still don't hold an advantage, but it's at least a little more balanced).

Damn I never played Mario Kart Wii but MK8 is damn hard for me to beat on 3 stars (still haven't beaten hardly any gand prix on 3 stars)! You are all damn good! 

This is why we have the blue shell

https://www.youtube.com/watch?v=LFfga8-3SZI

You bring up casual like it's the term to call people who play Mario games... I use it to describe "hardcore" Call of Duty players. Arguably if you use the definition right, most people that self proclaim themselves as hardcore something are actually casual and casuals are actually what I call, not meant to be offensive, unskilled players.

But Mario Kart 8 easy compared to Mario Kart Wii? Are you mad? Mario Kart Wii, besides that damn blue shell and bullet bill. EVERYTHING is easily countered. You can hold items behind you in Mario Kart Wii and pick up a new one. In Mario Kart 8, they removed the ability to pick up a new item while holding an item (and im glad they did). This forces you to learn to be more skilled!

Also you mention the blue shell dodging in Mario Kart Wii, as a heavy online player of that game, i suggest you sit down because what I'm going to say may blow your mind! There is two items in Mario Kart Wii, if you timed them right you can dodge a blue shell. They are the red mushroom and golden mushroom. You can't dodge the blue shell under any other circumstances other than the invincibility star or an item that gives you invincibility. If you so happen to have a bullet bill in first then you can too (but that's a rare chance)

Mario Kart 8 takes a bit more skill than Mario Kart Wii, especially in the higher cups. Smarter CPUs (cause of the Wii Us better CPU) are a big thing. Cause of the coin (a SNES classic item), you need to have skill to dodge items and watch for items as they are coming which brings more emphasis on the driving. Mario Kart isn't about the items, it's about how well you use them, avoid them and recover off them.

One last thing, the recovery time on being hit in Mario Kart 8 is much shorter because of the hardware, it's still not easier to beat skilled opponents at that game.

Who have told you that? Of course they could have choosen to use a shorter recovery time in MK Wii. Has nothing do to with the power of the hardware. Its just some settings and a lot of time put into adjusting these things...

But removing having to items at once means that you'll be more defensive while being in the first places. Even when having a shell it is better to put it behind your vehicle to protect yourself then trying to get the one in front of you...

No your wrong....there both equally easy and casual:)

They couldnt do a shorter recovery time in the Wii. The hardware itself was heavily limited cause it's doing a lot of processing between the hit, what the other player is doing, and the animations. Recoveries were much slower in MKWii cause of this hardware limitation. On the Wii U these recoveries last at most 3 seconds as you don't sit there for 30 seconds randomly spinning and flipping from items being hurled at you. 

As per your other point you are tryin to make. I called it artificial cheating. The point of Mario Kart, and in fact, ALL racing games is to be defensive (With the exception to games like Wreckfest). You're defending your spot. Items are there as a means for you to pass other players whom are more skilled than you are obviously. You can put the shells, and banana behind you in this, but I refuse to acknowledge the cheating nature of the other game which is easy to abuse. The new system is not easier and it forces you to get better at the game. 

I completely disagree. MKWii had bullshit luck difficulty. There's still luck in MK8, but they've definitely fine tuned it enough so that skill is a key factor.

Either way, MK8 is an infinitely better game than MKWii in pretty much every regard (except roster, but that's debatable). I'd rather have a better game than a more "hardcore" game.