Ferrari has more than just engine problems. It seems the whole car is off just by a fraction in each area. They need to look at the data and improve the car overall. Firing the team principal is not the correct move.
A few years ago, Brawn (old Honda/Tyrrell), was able to come up with one idea (diffuser) that set the field on its ear and got Button the championship. Mercedes seems to have found that one area in its engine design that sets its car apart above the field for now.
I don't think Ferrari will catch up this year to Mercedes. Alonso might be able to get some points and struggle to third or fourth in points but Kimi doesn't like the car and will not push.
Getting rid of Stefano Domenicali now is unwise and will hamper the team. Improve the car and get it competitive. Dismissing the team principal this early in the season is just a stupid knee-jerk move. Kind of like the old days of Todt being on the bubble each race based on how the cars did.