That's more of an old wive's tale than anything else. If a kit is going to die during a flash it's due to a hardware error, not because of the data being flashed.
Disassemble one of the leaked recoveries some time. You'll see that, unlike retail updates (which simply patch the flash), the recoveries wipe the flash and install a full version of the OS every time.
"Baby Stepping" as you put it, may make some people feel good, but it has zero tecnical impact on a system.
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