Simmons is contributing more than (nearly) anyone expected. Enjoy that.
Manu had the best court vision I have ever seen - ever. He made passes that nobody else could make. When he didn't have the angle, he would throw a bounce pass with english, so that it would skip left or right when it hit and get to his target in stride for an easy score. He made other players better, right from the start.
He was also much, much more elusive going to the basket. When he was perfectly defended, he would spin and come up on the other side of the basket and leave the defender(s) holding their jocks. When there was just time for one more possession, and the Spurs were down by 1 or 2, Manu would stand out beyond the arc and wait for the clock to run down, and then run through the defense like through a goose. Everyone in the arena knew he was coming, and they still couldn't stop him often.
Manu sucked out so many offensive fouls that George Karl actually complained that his long hair flying made it look like he had been hit by a truck. An opposing coach reduced to ing about a player's long hair? That's a compliment to his D, which was considerably better than Simmons' so far.
If you want to talk about Simmons' "impact" reminding you of someone, it's a lot closer to Derek Anderson. And that's not a bad thing for a guy who worked his way into the lineup, from virtually nowhere. Anderson was quick and athletic, forced the ball up the court and finished well at the rim, played above the rim A LOT, and defended a lot like Simmons at this point in his career.
Simmons impact is just not very similar to Manu at all, except for the fact that all points count. But, hey, fire away. At least you dilute the Apolisoc threads.