You wanted 200 steps, you are getting 200 steps, what is the problem?
Chip may be hot because you are taking too much power. Look at the spec sheet for the chip and motor.
I have a stepper motor clock **broken link removed** and I always turn off the power when not moving the hands. Runs fine, for months.
Constant current drive is not a requirement, but does result in better motor performance. It is sometimes done with a higher voltage than the motor requires, then inserting a dropping resistor. I often drive with out it.
You can of course get constant current with fancy pwm, chopping.... circuits.