My thoughts...
Keyboard - twice as expensive, no new functionality, still no backlit keys like Logitech's cheaper K810/811
Mouse - $20 more, no new functionality, hope you remember to charge it periodically as you'll be stuck if the battery dies.
Trackpad - One new trick, now costs as much as a Chromebook. Sad.
All use rechargeable batteries, so now instead of swapping AAs periodically I can juggle a Lightning cable between my peripherals. Also non-replaceable, so I get to throw out these ridiculously expensive peripherals when the batteries die.
21.5" iMac
No Skylake on the 21.5
Integrated video for a >4k screen? It's about as good as you'll find for integrated, but still...
Despite the huge drops in component prices over the last year, Apple's upgrade prices haven't changed in years.
256GB SSD upgrade for $200 (a decent one costs ~$75, or about $30 more than a the 1TB HDD you're upgrading from)
Fusion drive is down to 24GB(!) of flash on the 1TB model and that 24GB costs $100 extra. Yes, that's over $4.00/GB when flash prices are close to $0.25/GB.
16GB RAM upgrade for $200 (again, the extra 8GB costs around $30).
Rumors of soldered RAM? Have to wait for the teardown. The last model was a pain to disassemble but at least possible to upgrade.
27" iMac
Skyline... maybe? Strange since it requires a new socket/motherboard chipset. Have to wait for a teardown to confirm.
Fusion Drive finally in the base config, at least on the top model; lower models are sold with spinning disks and the pathetic 24GB fusion drive. Upgrades are ridiculously prices as mentioned before.
Only 8GB of RAM stock? The MBP has 16GB, seems like this should too. Not a big deal since you can upgrade yourself.
Still no Type C ports, so no TB3, etc. Yes, Dell is launching TB3 systems before Apple. Sad.
The M395X looks like a rebadge of the old M295X, which wasn't a great graphics card to begin with. It doesn't match the GTX 980M, much less the new 990M (which is basically just a cooler-running desktop 980)
I can see why they didn't spend time at an event for this; this is the most depressing Apple update I've seen in a while, and that includes last year's Mini fiasco. I swear they're trying to kill off their desktop line...