For skiing I would not really go to Ischgl only for the park. Because most of the slopes are very flat and the area is a little bit wired. You often have to take the lift where you often have to wait long because there are many people waiting. Also the slopes are very crowded especially at the end of the day the run down to the valley mostly is full with beginners and drunken people which are heading back to the hotel. This is an adventure run could be also quite dangerous because of that not very fun to go with kids down to the valley. There is some space for freeriding but therefore I go to other areas.
I did not make party in Ischgl, but for its party nights Ischgl is famous for. If you walk through the cillage you can imagine what there is going on in the evenings. The village is lovely there are some nice shops and restaurants.