It looks like this is just some kind of big, luminous quadrant sight and lacks the ranging and impact point calculation facilities of the PSQ-18. It also looks to not weigh as much as the 203, unlike the PSQ-18. Cool...
The problem with the new sights the Army wants to field for the M203s is that they are all too complicated. The sight that's coming on the new 40MM grenade launchers requires you to lase your target to get a range, then eyeball some green and red lights to line up the perfect elevation and windage. That's fine and dandy on a quiet range at the proving grounds, but every M203 round I've ever seen fired in combat has been a "Oh ****, I gotta fire a 203 round at that clump of trees over there! But there are so many rounds coming my way I only have a second to acquire my target and shoot. Looks about 200 meters, pop up, WHOOMP, ahh hell I missed anyway." Not much time to pop up, lase, range, line up some dots, then shoot a round that's probably not going to hurt it's target anyway.
This Eotech sight is much better. You can guess your range, pop up, and use the BDC reticle to figure out how to angle your launcher. Much faster. If the thing is paralax free past 50 meters like the rifle sights, that's even better. I'd like to take try this sight out.
Suigenesis hit it on the head, most of our grenadiers who were issued the M203 had some hunting experience and were able to "kentucky windage" the 203 pretty well. As previously stated, it is near impossible to properly line up the new electronic sights under fire, but if it helps enough to offset the increase in weight, go for it. That said, there's already so much weight on an M203 equipped M4's front end that it's become wholly impractical. IR laser, surefire light, maybe a leaf sight, the 203 itself, the round, it all adds up. Some guys add bipods or vertical grips to it as well. What's on the other end?
A plastic butt stock.
Perhaps this change to a modular M320 is for the better, and the ability to "M79" it would allow it to be stowed like a breaching shotgun or left behind altogether if warranted.