I thought read somewhere that the reason why we are not getting ICS as soon as HTC said we would is because they are going to release it with Sense 4.0 instead of 3.6 like our ICS leaks have.
Supposedly, single core phones will get ICS with 3.6 and dual cores will get 4.0. I can't remember where I read it though. So please don't yell at me if I misread something and am completely wrong...
HTC Eris=>Thunderbolt=>ReZound=>Droid DNA=>One=>Nexus4
Amazon Kindle Fire=>Samsung Galaxy Tab 2 7"=>Nexus7
Samsung Galaxy Player 4 w/Voodoo