Changing from .40 to .45 won't help with this. Sounds to me like you just need more range time and plenty of dry fire practice. Focus on the front sight, squeeze the trigger, and let the shot surprise you.
I agree. Sure, the .40 is usually considered more "snappy" vs. other loads, but to me this argument is somewhat egregious as almost any "heavy" caliber comes with a learning curve. If you want simple to shoot/precise loads, by all means, go with the .22 or 9mm. But, at some point, you will have to learn to adapt to recoil. Being accurate with a .22 does not mean one will be accurate with a large caliber weapon, IMHO.
Hence, besides trigger management, recoil management is of paramount importance here. Learn to deal with the recoil. Once this becomes second nature, focusing on trigger management and the like will be much easier for you. At least this is what I believe.
Having said all of this, it does seem to me that more range time, along with specific focus on the fundamentals of shooting/weapon familiarity, may be of more benefit vs. simply relying on a different caliber in hopes of improving things.
Also, I personally do not believe that going with a .45ACP will make much of a difference. Given that you already shoot a .40, if you want to truly make a difference, in terms of ease, I would go with a 9mm (not a .22 as others have suggested). The .22 would be good if you were a child starting off for the first time. But, as an adult already acquainted to the shooting world...there is no immediate need in going that far back, IMHO.
If you are simply considering the .45ACP as an alternative to what you already have, I would stick with the .40. Give it some time. Learn to manage and get used to the recoil. Also, as suggested before, try plenty of dry fire practice (good for trigger management, however, not compensatory in terms of recoil). Is the .40 S&W ideal for starting out? No. But, then again, neither is the .45ACP. However, simply because you are not able to consistently hit at POA, this does not necessarily indicate that you need to switch calibers.
Sight adjustment? Maybe. More practice? Yes. Implementation of the fundamentals of shooting? Yes. A dire need of changing calibers? IMHO....no.