Williamsburg is an interesting one partly because of the operational environment and partly because of the command environment.
In the operational environment, it was pretty much the AotP pursuit after the abandonment of Yorktown while the other half of the Union army moved up the York river to Elthams Landing (which would have formed a blocking position if the ANV had moved too slow, but which instead basically just meant the ANV couldn't defend at Williamsburg for long despite it being a prepared defensive line).
In the command environment, it was after this battle that McClellan basically wrote to Lincoln saying "all my corps commanders are awful, can I replace them for it?" and Lincoln replied "no" but gave McClellan permission to temporarily alter the corps structure - he just couldn't fire anyone.
This led to the AotP's five-corps structure on the Peninsula, as McClellan created 5th and 6th Corps so he could put commanders he thought were worth a **** in charge.