If He wills, He can remove you and bring (in your place) a new creation! And for Allah that is not hard or difficult.
means, it is not hard or impossible for Allah to do that. Rather, it is easy for Him, that if you defy His order, He takes you away and brings in your place another creation who is unlike you.
Allah said in other Ayat,
يأَيُّهَا النَّاسُ أَنتُمُ الْفُقَرَاءُ إِلَى اللَّهِ وَاللَّهُ هُوَ الْغَنِىُّ الْحَمِيدُ
إِن يَشَأْ يُذْهِبْكُـمْ وَيَأْتِ بِخَلْقٍ جَدِيدٍ وَمَا ذَلِكَ عَلَى اللَّهِ بِعَزِيزٍ
O mankind!
It is you who stand in need of Allah. But Allah is Rich, Worthy of all praise. If He willed, He could destroy you and bring about a new creation. And that is not hard for Allah. (35;15-17)
الْفُقَرَاءُ وَإِن تَتَوَلَّوْاْ يَسْتَبْدِلْ قَوْماً غَيْرَكُمْ ثُمَّ لَا يَكُونُواْ
And if you turn away, He will exchange you for some other people and they will not be your likes. (47;38)
يأَيُّهَا الَّذِينَ ءَامَنُواْ مَن يَرْتَدَّ مِنكُمْ عَن دِينِهِ فَسَوْفَ يَأْتِى اللَّهُ بِقَوْمٍ يُحِبُّهُمْ وَيُحِبُّونَهُ
O you who believe!
Whoever from among you turns back from his religion, Allah will bring a people whom He will love and they will love Him. (5;54)
and,
إِن يَشَأْ يُذْهِبْكُمْ أَيُّهَا النَّاسُ وَيَأْتِ بِـاخَرِينَ وَكَانَ اللَّهُ عَلَى ذلِكَ قَدِيراً
If He wills, He can take you away, O people, and bring others. And Allah is Ever All-Potent over that. (4;133)