I would think that there's probably a bunch of things that had to be back ported to Tiger when Apple announced a 1 year delay.
I'm sure there were probably some features that weren't worth the back port and were bastardized or eliminated all together.
Hopefully we'll see some nice feature upgrades to iLife and iWork once Leopard gets rolled out.
With all this iBricking and locking out software, I hope they aren't reserving all those icon spaces on the iPhone / iTouch for corporate sponsored advertising spots. First you had Starbucks, how far behind is a McDonalds tie in or a Burger Dudes for that matter.
If that starts to become the case, I'm using mine as an iDoorStop and getting a new phone.