I respect your reasons and I'm glad you're happy with your N9. But for me: I won't miss the iris-scanner when there's a front-side fingerprint scanner; I don't care about the LEDs if the screen can show the same notification lights; the N10+ is just 1mm taller, and 0.5mm wider, than a N9 (and the N10+ is 1mm thinner, thus 10% less size overall, than the N9); I've never used close to 256GB (but the N10+ still accepts an SD card); I doubt I'll notice the cutout, and a hole is better than missing an entire edge of the screen (N10+ height is 3040 pixels, vs 2960 for the N9); I seldom use wired headphones but if I want to, the N10 comes with USB-C AKG headphones; I haven't heard about the notification-bar size, but if even if it's not software-configurable, it doesn't matter for full-screen apps; I've never used a case for my phone (and my screen has never ended up scratched or cracked), so I won't need a new one; my N9 chargers will still work, plus the N10 comes with a new 25W adapter.
I wouldn't pay $1100 for a N10+. But it's not implausible to pay $500 to trade a N9 for a N10+ with a credit for BT earbuds.