These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Neither the Irish names, accents, or landscape is integral to the plot, raising the question, how is this a world "where Irish myth lives"?
It's a complete coincidence, but Power Rangers Samurai has the same five elements, fire (red), water (blue), forest (green), earth (yellow) and air (pink). Forest and Air were Wood and Heaven in Samurai Sentai Shinkenger, so it certainly wasn't intended to match Mystic Knights, it just did.
Forest and Wood are the same, it's just that Wood has Double Entendre jokes in the West. Heaven was meant as Air. The two are the same because Wood isn't exactly an uncommon Element Number Five.
Visual Effects of Awesome: CGI aside all other effects like the sets, the costumes, the battle scenes, and especially knights' armor looked very good considering it was a Saban-Production.