In some areas it's an improvement. But in others, it's more of a downgrade.
Old Deck vs. New Deck
Generic back - Celtic-inspired design
No English, all Celtic - Celtic and English
Clean design - Hopelessly cluttered
Showed proper quantity of Celtic-inspired pips - shows a single Celt-esque pip in the center with a number (WTF?)
Then there's the biggest problem of all - even in the Republic of Ireland the Celtic language is nearly dead, with fewer and fewer speakers learning it from birth by the year. I have to say, when hankering for a pack of cards to play a little solitaire or a few rounds of poker with the guys, the furthest thing from my mind is "Gee, we should get a pack of cards that's partially printed in a dead language that no one at my table knows, including myself...because it's so much uglier than my plain ol' USPC standard faces..."
A successful deck has an audience that wants it, whether they knew it before or not. The designer sees a potential demand and creates a design that will fill that demand. This deck is looking for an audience and has managed to trim its potential customers to a very short list - a smattering of language professors and the natives of a few remote regions of Ireland that don't interact a lot with the rest of the world...
People do still learn Gaelic - but they also still learn Latin and Ancient Greek. It doesn't make any of those languages any livelier than the others on the list because of the really tiny numbers of native speakers who've been learning Gaelic as their primary language almost from birth. It used to be that all the road signs were in English and Gaelic to accommodate the Gaelic-speaking population - now it's more because it's quaint and the tourists like it. The language was almost commonly used in the early 1960s but its decline from that peak was swift and sure.