Interesting to see that they are hoping for 1.4 million visitors by 2020. Ireland is a country of 4.8 million people, make that 6.4 when you count Northern Ireland as well. Roughly a million people live near Dublin, where the park is located. A park with 1 visitor per 4 inhabitants in a country (or 1.5 visitors per inhabitant in a city) is a pretty bold goal to reach for. For comparison, Thorpe Park has ~2 million visitors per year, servicing the Greater London area with 9 million inhabitants (and 65 million annual tourists), the capital of a country of 55 million people. The current visitor numbers for Tayto appears to be in the range of 800,000/year.
Then again, Norway's biggest amusement park had 1.1 million visitors in a (long and narrow!) country of 5 million, so I guess the numbers aren't that unfeasible. But that park is also the family park in the country and contains a large zoo, and I don't think Tayto is catering that hard to families?
Don't get me wrong, I'd really like to see them increase their visitor numbers by 75 % in four years. But I think it is a very lofty goal to strive for.