I've used the microsoft natural keyboard 4000 for damn close to 20 years now and there is a seperate set of arrow keys directly to the right of the main keys between them and the number pad. It just works for me, especially after many thousands of hours use.
I just tried the feel of your IJKL and it feels okay but still a little wierd to me. I could probably get used to that if I had to though.
edit: oh and as to the keys around there are several. ie: insert, home, pgup etc and the number pad and the right ctrl and shift buttons etc. For example my reload button is always my delete key.