I'm not sure why everyone is so high on Leonard. He's either the next Aaron Afflalo, or the next Jimmy Buttler. Except we can't really know yet.
Neither of those comparisons gives me much confidence at this point.
I think nearly every NBA team would like to have a healthy Jimmy Butler clone on their team right now.
He's having a good season, that's about it. Are you willing to roll the dice on a 4-5 year MAX contract on him just because he's having a very good season?
That's usually how mistakes are made.
Because this needs to be mentioned every time someone argues against a MAX contract, especially when capitalized:
1) Not all max contracts are equal. Butler will be eligible for a smaller max contract than LaMarcus Aldridge, for example (about 16% less in year 1).
2) If the celtics somehow signed Butler, he'd be paid approximately 18.5% of the cap in year 2 of his contract, which in 2014-2015 cap dollars would be the equivalent of making $11.7 million under the current cap. A player making $11.7 million would be the 50th highest paid player in the NBA. It's pretty unlikely that paying Butler that amount will make him an albatross that breaks your team. Of course, because of this fact it's all moot, as the Bulls can match any offer, and will do so, especially if it's a 4-year contract.
And 3) I'm well aware of what a MAX contract entails.
Though I think your figures are a bit understated. For example, you take a Gordon Hayward on his year 3, and unless you're using different figures than the projected cap for 2017, he would be making about 20% of the cap.
Butler's contract should be more expensive than that I would project with 2015 projected numbers.
That said, this has nothing to do about paying the MAX or not. I use MAX and MIN in capital letters just because, not to accentuate it.
The main point here is if one is willing to invest on a player, heavily, reducing buying power as it is, on a player that has a single season of actual great play to go for it.
It's more of evaluating if this is a player that is projected to continue to play this well beyond this year or not. I'm personally not ready to give that contract without much thought and evaluation behind it. If at the end of the day you do feel this season is not fool's gold, then heck, go for it.
I'm not sure if Butler is that player. I rather keep more options open, particularly when you consider that the abundance of 1st round picks will be eating up our salary cap quicker than one might think in coming years. There's a huge consolidation process that needs to happen.
But as you mention, Butler if he doesn't live up to it, it's not a albatross that would break our team. That doesn't excuse throwing money away.
In the end the question always will be for me... is this a one-year wonder player?