Yes, they have. I visited last year and it's absolutely amazing. So is Pir Suhawa and Saidpur village. Absolute must-sees.
God bless Gen. Musharraf for doing all this. Under his leadership Islamabad saw a lot of development:
1) Centaurus
2) Daman-e-Koh
3) Zero point flyover and numerous underpasses
4) the breathtaking Rawal Lake Park
5) Lok Virsa Museum
6) Saidpur
7) Pir Suhawa and Monal restaurant
8) New Skyscrapers: ISE building, Telecom Tower, Hotel Intercontinental etc.
9) Pakistan Monument, gardens and museum
10) Several new parks and upgrades to existing parks
This is a short list, obviously, but what a renaissance the already gorgeous Islamabad went through under the General.