If you can keep your work rate down then breathable waterproofs can cope but you may get clammy on hill climbs. Waterproofs are for use in the rain only, lighter and cheaper windproofs are better in the dry and in very light rain.
Windproofs in heavy rain will soak through and in cold weather can be uncomfortable unless you have fleecy style mid layers.
On the legs I find that anything heavier then pertex is unneccessary even in heavy cold rain. My Freestyle pertex have carried me through 8 winters so far.

You can wear a formal work shirt on a gentle ride but for anything athletic, roll it up and carry your shirt in a bag.