If they go with the "PHBX every year" plan, they probably wont need to do a whole scale revision. They will just quietly and with little fanfare introduce optional rules that will eventually become the new standard, while also updating original source material from the Digital Initiative.
Think a 1984 style revision of history. To borrow from 3rd edition to 3.5... "There have always been size categories for weapons. The Haste spell never allowed a caster to cast two spells. Harm allows a saving throw."
If they handle it like that, the only inconvenience will be the growing discrepancy between your hardcopy and the Digital version online. But for your convenience, you can upgrade your PHB1 to the corrected version by purchasing a new copy at Retail.
And before anyone actually jumps on me for trying to be anti-4th edition here, I actually like that way of handling it. As long as the digital version is kept up to date and you can access revised rules even if you have an original printing of a PHB, it should work out just fine.
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