As always, I both like and dislike iterative attacks.
One thing I like about it is that it makes me feel as though I have contributed something during my turn, while striking a middle ground between feeling useless and doing too much.
Let me elaborate. Say I am a warblade using a standard-action strike. When I attack, one of two things happen. Either I hit for a lot of damage, or I miss and do nothing.
But the way iterative attacks are structured, I typically hit with my 1st 1-2 attacks (possibly 3 with haste), and miss with my remaining 2. So I don't feel like my turn was a complete waste. It is a good way of spreading out the damage so combat does not become too binary.
But I dislike that you are more or less expected to miss with your iterative attacks, and that many attacks tend to bog down the game. I am thinking that perhaps we should follow the decisive strike monk variant in PHB2. Mathematically speaking, I think that +20/+15/+10/+5 is roughly equivalent to +20/+20 (according to a study done at enworld).
So give combat classes fewer but more meaningful attacks.