I didn't know Sa Coma was geting a water park? Maybe someone can let us know whats happening ?

Im not sure if this has anything to do with what you have heard, but try this link http://www.thomson.co.uk/destinations/europe/spain/majorca/sa-coma/apartments/protur-safari-apartments.html

It makes reference to water slides and wave machines but not sure if it is a waterpark in the same league as the ones in Arenal or Magaluf.

The small waterpark is at the back of the Profur Complex, it is mostly designed for families with smaller children.
There are no large slides, there are two water pipe flumes probably 5 metres high. There is a kiddies pool that is inches deep, and a main pool that goes to about 5ft deep. There are plenty of sunbeds and umbrellas.
The actual place is superb because they only allow a set number of people in , you pay an all inclusive price(special rate for guests of Profur) which includes all food- breakfast, lunch, afternoon tea. The drinks are all free as well, which includes a swim up bar !!!!
If you have teenagers they will get bored, but for couples or families with younger children it is superb.

Sorry forgot to add, there is no wave machine.

Sorry again - forgot to say that there is free basic ice-creams and lollies as well.