I have long wished ranged characters could use expertise. That certainly would help them since AC is an issue.
And shadooow is right, you can add many properties to bows (ect...) with CEP too that aren't default (e.g. keen.)
Regarding #2 doesn't the game automatically use str for attack rolls (ranged or otherwise), unless dex is higher and have weapon finesse (and is a finessable weapon), or wis is higher and have zen archery?