Call me paranoid/pessimistic (neither is far from the mark) but it seems NoE has either fallen behind and is struggling to catch up, or is so undermanned they simply can't localize games fast enough.

First we saw Captain Toad pushed back from December in NA to January in PAL.

Then Kirby and the Rainbow Curse released Feburary in NA, and is coming to PAL in May.

Now there's rumours that Splatoon has also been delayed in Europe and Australasia, which seems a sadly plausible outcome. 

Could the knock on effect continue, and go on to impact later games like Yoshi's Woolly World, Xenoblade Chronicles X, Starfox?

Yayy! Where is ktay at cause this is revenge for him rubbing the n3ds all over our faces!!! Take that ktay! You may have the awesome looking faceplates but we get the games first!

But yea, I can see yoshi getting delayed

It sucks codename steam is arriving in May for Australia. If we get Xenoblade, Starfox and Zelda later than the NA, I am just going to lose it.

i suspect that the 'B' list games are getting delayed in order to ensure that the 'A' list release on time. It would be disastrous for Nintendo is European gamers faced a significant delay on Zelda/Splatoon/Xenoblade, so I suspect they're prioritising their localisation efforts accordingly.

or maybe the WiiU is more popular in Japan and America?

Kirbyis now releasing in May, and it was slated for the 2nd half of 2015, so in this it is a positive way it turned, don't you think?

And Splatoon won't be delayed. Just wait a few days.

NoE still has plus points on my list from the Wii-Generation (Disaster Day of Crisis, Project Zero II, also Xenoblade+Pandoras Tower+Last Story without begging). A few delays won't change my oppinion that NoE > NoA.

One month delayed is not big deal.

Dunno why Nintendo insists on staggered release dates still. It's a pretty antiquated practice at this point. If NoE is undermanned and it's taking longer to localize the games, they need to get more man power to get the job done. Otherwise they really should just project a realistic release date that allows for simultaneous release across all regions. I understand that sometimes it makes sense to gauge interest in a title by releasing in one region first, but these are all new IP or well known, neither of which should be having these issues.

It takes a lot of time to translate the text to all major European languages.