Sorry I can't tell if concurrent processing gives better chance for AIP or not, it will definitely depend on your case, so make sure to work very well on your file and add as many proof as you can to prove why your relationship is genuine and why your removal will impact your partner and expecting child (did your wife have close family that can help her with the baby if you are not here anymore).
Don't base your entire h&c application on your expecting child, since your child is not born yet is best interest will be hard to determine. If his mother is completely capable to take care of the baby, officer can decide that your presence in his first few years is not necessary, as more the child lives with the parent more is best interest will be impact if this parent is far from him( if it's make any sense).
Add some establishment proof and genuine relationship proof that lacked in your previous sponsorship. Read your refusal reason in GCMS note to see how you can erase those concerns.