Little endian is no more natural for a computer as big endian. The only difference in hardware is how you calculate the strobes and shifts. 32 bit values on a 32 bit bus are the same whether it's big endian or little endian, it's only when you access bytes or words that anything changes.
I dunno, when you stop to think about it, most big-endian processors that support different size operations on register operands tend to do so as if they were little endian. For example, .b and .w operations on 68000 registers always affect the least significant byte and and 16-bit words respectively. Similarly the PowerPC performs byte and halfword operations on the least significant portion of the register. However, when it comes to memory operands (where supported), suddenly it's a different matter.
Conversely, little-endian processors like x86 tend to be consistent in that accessing a byte at a particular address modifies the least significant byte of any wider type considered to exist at that same address, as if that address were just another register.
