I agree that heavy compound work should be the basis of every workout. I stand by that. Hypertrophy training is much different than PLing style though and should be utilizing many facets and methods to achieve the goal of muscle growth. The OP did mention that the only body part lacking was his chest. This is mainly genetics. It can be overcome with specific hypertrophy training in conjunction with compound movements. I liken these scenarios to squats..most people say squat big and you will get big calves. I squatted big and never saw growth until I added BBing routines for them into my PL workout. The combination is the key.
Ok ok.
First of all, I'm currently a competitive powerlifter, but like most people who compete, I've spent some time doing both endeavors. I am qualified, lmao, thank you very much, to have and state my opinion. I work with (and occasionally train with and/or train) a few competitive body builders, and while their training is quite different than mine, at the end of the day we do many of the same exercises and get many of the same results.
You state, and are correct, that the big are not always very strong. I agree 100%. They are
all strong though. I've never, not even once, seen or heard about a guy who is considered "big" who wasn't moving respectable weights. Unless you've got a very small frame, a 200 lb bencher just isn't going to have that much musculature. It comes with the territory; having a bigger muscle will
generally result in more weight being moved. Likewise a 450 lb bencher might be a 165 lb guy, but that's near world record levels, and just not typical. The original poster is a somewhat new lifter, it is very unlikely that he'll look substantially better with regard to muscle size without getting significantly stronger.
If you reached a point where you did more on dumbbells than a straight bar, it pretty much had to be a form issue. Maybe you did the barbell much more strict, maybe your dumbbell range of motion wasn't that great, maybe your bar path on bench was very much sub-optimal and your dumbbell pressing path was perfect. I'm not specifically trying to argue with you here, but I've NEVER seen an exception to this without form being an issue. You are correct that the body will adapt to certain training loads, but there is only so much you can do to change stabilization/etc.
Most people do not realize the importance and role of triceps in pressing. Just because your triceps don't "feel" more pumped doesn't mean they aren't relatively weak compared to your pecs and holding you back.
I am very much well aware of the difference between close grip and regular grip bench. I am also aware that they engage different muscle groups. Follow me here...
1: My argument is that with most lifters, the triceps are a significant weakness that in my opinion, holds back weights used and development of associated pressing muscles.
2: Since I already believe that triceps are a weakness on something like regular grip bench, moving over to close grip bench, which will tend to put MORE emphasis on the triceps will expose the same weakness.
Does that make sense to you?
As far as your statement that genetics play the big role in size vs strength.. well... sure... but that's pretty much on every lift. I would still go through the same basic motions.
One philosophy that I employ is that everything is weak and needs to improve. At 157 lbs I figured his goal would be to get larger and stronger, but maybe I shouldn't have made that assumption.
The bottom line is that my opinion for the OP is that he should concentrate on gaining some overall size and strength before worrying too much about ratios and proportions. Don't major in the minors. Of course I think he should ensure that he's properly performing the exercises, and of course I think he should put a little extra into areas that he believes are lagging. If I were him I'd work that close grip incline, get some extra calories, and make the numbers go up, both on the bar and the tape measure.