You're not demonstrating causation with these statistics; you're just cherry-picking positive numbers (like On/Off per 100 possessions, as if this was the key indicator) and posting them.
I think those numbers do demonstrate the following idea: Kevin Love is so good at so many things, that his presence on the court is a key ingredient to the well-being of this team.
First and foremost, the spacing provided by Kevin Love is extremely valuable to the success of our offense. The fact that he's hitting threes at a higher clip makes our offense more potent, and he opens up driving lanes for Kyrie and LeBron. Love HAS to be respected, he can still take games over. This in turn opens up the game for LeBron and Kyrie to start the lay-up line and it increases the quality of shots for J.R., Iman, Delly, etc.
The counter-argument to that is "Why are we relegating Kevin Love, a max player, to being Channing Frye??!!??". While I do think we can use Love better and over time increase the diversity in which we get him shots, I still reject the "we can get the same thing for cheaper" argument for a few reasons.
1. Defense. Defensively, Love has shown that he is a willing, smart, and capable defender now that he isn't asked to be a rim protector or defensive anchor. He generally hustles, gets to the right spots, and has active hands. I'll never mistake him for an awesome defender, but he plays the game the right way on that end, at the very least.
2. Multi-faceted threat. While still not used completely right, Love is still a post threat and still a mid-range threat. He must be respected, unlike any random replacement "stretch 4" and he must always be gameplanned for.
3. Elite rebounding. Our rebounding clearly suffers when he's out/doesn't play. He finishes possessions, boxes out, and goes hard for rebounds. He doesn't "stat pad" very much with his rebounds. He earns it. At least that's how the results of my eye test worked out over time. He gives you way more on the glass than you would find from any average stretch-4.
4. Ball movement, starting the offense, passing. Stemming from his defensive rebounding, Love is one of the best tools we have to pushing the pace. I'm not even talking about his home-run passes full-court. Even when those aren't available, he is constantly looking to get the ball out to a ball handler as far up the court as possible. He hits those guys in stride and really makes it easier on the guys who have to bring the ball up the court by making them dribble a lot less than they would normally have to. It really helps start the offense. Once we are in the offense, he moves the ball really well. He makes the right passes, he runs the plays. At an elite level for a big-man. Not really a replaceable skill. His passing is very good for his size. He can create buckets for others. He actually feeds the bigs really well, go figure. We can also do a better job using his passing to our advantage.
Nonetheless, I think these are the main things to look at that show why Kevin Love's presence makes us so much more successful, and so much more likely to go far in the playoffs. I think it also helps justify the Wiggins trade as something that had to be done and has had a positive impact on our chances to win a championship while LBJ is still the best player in basketball.
