Пока лучшее, что смотрел - "Bitcoin, the end of money as we know it". По-русски разумеется нет

I have an idea to make a secure keypair generator for myself.

What if I use raw 32-bit private key the way so I use 30 bytes for the key and two bytes to be like an uint32_t type integer (valued from zero to 0xffff).

Like so:   
XX:XX:XX:XX...(30 true random bytes) + YY:YY (index)

Are there any serious drawbacks compare to original BIP32?
It looks much more transparent and easy to code