I had a Cherokee 140 and used to fly a rental 140 regularly. The rental would do as the book says, and would fly off more or less on its own with gentle back pressure at book speed. On the other hand, mine fairly had to be yanked off with a strong pull of the yoke, and it would stagger into the air and need some time in ground effect to regain its composure (my current ride, my Beech Sundowner, fairly leaps into the air when you rotate at 65 knots, no matter what the load).
One thing to check on Cherokees as a contributing factor: the pressure in the main and nose gear oleos. Some tend to sit low on their main gear with a nose-high attitude, some have a nice perky stance if the oleos are properly inflated. Sitting nose-high will give a higher angle of attack, and this will signficantly affect behaviour at rotation, more than likely even more serious at high density altitude.