With all transmissions, you will experience 'some' engine braking; however, every type of transmission may allow for more or less engine braking. This is normal... unless it is 'braking too much'... if that's the case, you may want it inspected.
The brake fluid should only need to be changed once every two to three years and the caliper slide pins should be cleaned and lubed as needed. If the factory lube was not sufficient, I would have a shop clean and lube the caliper slide pins.
Do you notice any rubbing noises or vibrating at highway speed? If so, it sounds like the brake caliper may be rubbing. Sometimes, the rotor gets 'slightly' warped, or the caliper doesn't fully release and just barely touches the rotor. This can cause a rubbing noise, vibration, or pull to the left or right (like alignment or wheel bearing).