What you say is true and you could benefit from a reduction in the Abilify, though it's important to remember that there are a lot more neurotransmitters than just the dopamine system affected by atypical anti-psychotics like Abilify, so you may not get the relief you want. The effects on certain 5-HT receptors give Abilify many of its anti-depressant and anxiolytic qualities, and it even has an effect on serotonin, so you could end up more depressed when you lower your dose. The only way to find out is to experiment with lowering the dose.

There are also a lot of anti-depressants available which don't interfere with anti-psychotics, and adding one of these would be an option for your depression if you find improving your lifestyle isn't enough.

Good luck!