Same as challenge modes though - the better gear you have, you still have an advantage albeit slight. More gem slots for a start. Even now, a very very very well geared (say BiS) protadin can have 20 gem slots each with 320 haste in. That's 6400 haste just from gems, and believe me that's more than you have in full 463 gear if you get hit and exp capped. Also, as hit and exp remain unchanged, higher gear = fewer items with hit and exp on as the numbers are higher. This leads to more items with other stats on, so whilst scaled down, you will still have more of them than the first time round.
Yeah your haste will tumble and it'll suck, but you'll still have more stats than if you actually had 463 gear, just due to item budgets and reforging and stuff. A noticeable amount but that's only because of how low they can actually be