For me the weird thing right now is that attack feels OP relative to defense. Largely because a tactical player will rarely if ever engage when they don't have first-strike. So I find myself running the later levels with 40 ATK and 4 DEF (of course if I screw up, I die in one hit)
I think this will change when you are going for relic pieces and time is of the essence. You don't want to dance around for 5 turns to get the first hit when you can have defense and have a good chance to not get hit and save turns.
For sure a 40 ATK 4 DEF build is faaaaaar more useful than a 4 ATK 40 DEF build; but you wouldn't find me running either. Sometimes you just can't help but take a hit, so all attack builds are hella risky.
About the ratio in general, yep, attack is generally more powerful than defence. I've come to think of this as a positive though, if the two were balanced the answer to "which do I want more of?" would always be "which do I have least of"; this way, you need to decide how much more valuable ATK is to DEF for you.