I'll participate in the tournaments if I remember when they happen. I think I have missed three total since the game launched, so that's not so bad considering I'm pretty forgetful.
You can dodge the blue shells in the exact same way in Double Dash!!.
I never could get it to work. The timing must be a lot more exact.
You don't need to trail Items to deflect shells, you just have good timing.
That was my point, it is a lot harder to block oncoming shells in Double Dash!!. There also isn't a rearview camera, so you can't see where the shells are until right before they hit you giving you a very small window of opportunity.
Even with the extra four racers in MKWii, I still think the items are worse in Double Dash!!. After all, there's a character dedicated to items so they're going to play a pretty big role.
I should say, however, that I enjoy the unpredictability associated with random elements, so that's probably a big part of the reason why I don't find the items in MKWii to be a pain.