I have the exact same problem on my 2004 EX coupe 6mt.
I took the car to two different dealerships. Both of them said this normal for power seats.
I wasn't satisfied with their answer and called the Honda customer service number and opened a case number. A Honda rep. called me about 6 days later and told me that "the seat works as it was engineered". I ask if the drivers seat was engineered with play in them for a reason. He side stepped the question and repeated. " The seat works as it was engineered". I also asked him if anyone else had complained of this problem and he told me "no". I figured he was lying or was stupid or both.
My guess is that there has not been enough people complaining and taking it to the next level to warrant them spending money to resolve this. Most of these complaints get shot down when people accept the service managers corporate answer.
If everyone who has this problem would call the Honda customer service number and open a case maybe it would raise some eyebrows at Honda Engineering.
I am probably going to take the easy and costly way out by selling and buying a new car. Seat problem not severe enough to bring lemon law into play ( and Honda knows this). Only other remedy would be if there were enough people to get a class action suit going to fix this or if there was some kind of safety issue. Not likely to be a money maker for a lawyer and Honda also knows this.