Hopefully it will be better than the shitfest that was GTA IV.
As for making the main character Irish it makes no difference to me.
San Andreas was the best GTA to me and I'd like to see it go back to that style.
I preferred it over the Saints Row series which isn't bad.

If I want to get my GTA-style Irish fix on, then I just pop in "The Saboteur" which fucking owns.
It's 1940 in German Occupied France and you play a pissed off Irish race car driver (Cheated out of the 1940 Sarrbrucken GP win by a Nazi Colonel) who joins the French Resistance to start fucking up Nazis.
The main character in the game is inspired by the life and exploits of William Grover-William.
He was a very colorful man who went from being a GP Champion (Bugatti) in the 1920's/1930's to being one of the main SOE Agents in the French Resistance before being executed by the Nazi's in 1945.