If its going to be easy to heat your wort to perform a mashout step with this new system, I do recommend it. But if its a PITA, then there is no problem with skipping it.
There is no need for a sprinkler in your system, as long as there is some wort depth over the grain bed. A lot of brewers place a hose on top of the bed and just let it flow. Others include a floating cap over the wort with some sort of port that allows the return flow to get under the cap. The cap reduces oxygen contact and reduces heat loss.