Again yes yes yes it is needed.
On a military rifle, sometimes. Not so much on a civilian model.
It is a part of the AR platform that evolved out of a very serious need (an extreme need in Vietnam) to address certain problems that are part of it's design.
What problems are part of its design that require the forward assist? Which of those problems apply to civilian life?
Removing it is a step backwards not forwards. The AR platform despite all of the refinements added to it over time is still prone to malfunctions especially those of the type that need a foward assist to correct.
Name those malfunctions that need a forward assist. I'm assuming you mean "can't clear without the forward assist," when you say "need a forward assist." So, name some.
It is a weapon you best maintain meticulously and much more so than than your standard firearm or you are going to find yourself in a jam (pun intended)
Bull. ARs don't require any more meticulous maintenance than any other firearm, particularly those in civilian hands.
After running a large amount rounds through it you will need that forward assist and having an AR without a dust cover is just plain asking for trouble.
After running a large amount of rounds through it, you will need to
clean it. Because you'll be on a range doing that. If you're running enough rounds through an AR to cause problems due to fouling during an actual fight, you're not a civilian.
Dust cover is irrelevant. You aren't closing after every shot, are you? Are you dragging it through the mud when you're taking it to the range or out of your closet? No. Civilians have no real need for the dust cover, either. Military has very little need for one, but it's handy in some conditions.
I think AR makers had better find another way to be a cheapskate because this won't fly well with anyone who knows the AR platform.
I'm pretty familiar with it, having been in the military and been an armorer. (Unit level, mind you, not my primary MOS. Still, trained well above the normal level on maintenance on the weapons in use at the time.)
Being familiar with the AR rifle, lack of a forward assist or dust cover wouldn't prevent me from buying an M&P Sport. (More attractive packages at a slightly higher price point would, particularly those that come with things I'd want to add to the Sport, but that's another discussion.)