No. This is the
current to-hit formula:
As the player's attack bonus goes up, the overall chance to hit increases only by a little. As the target's armor class goes up, the overall chance to hit goes way down. And the end result is rounded to the nearest 5%, which means a small increase in attack bonus may not even result in a greater chance to hit. So the player's attack bonus is far less significant than the target's armor class. Let's look at the effects of the to-hit penalty from two weapon fighting as an example.
Assuming you have the
two weapon fighting feat (because why would you be two weapon fighting without it?), the to-hit penalty for both hands is -4/-4 when wielding a non-light weapon in the offhand and without oversized two weapon fighting. A difference of 4 in the formula above will end up being around 1%, which is unlikely to change the final chance to hit because it is rounded to the nearest 5%.
So let's use an attack bonus of 60 (including the -4 twf penalty) as an example, which is very easy to achieve by pretty much anyone at endgame.
(60 + 10.5)/(target AC * 2) + 20%
70.5/(target's AC * 2) + 20%
35.25/target's AC + 20%
Now let's try a few different numbers for mob AC (I have no idea what mob ACs actually are).
35.25/60 + 20% = 78.75%, rounded to 80%
35.25/50 + 20% = 90.5%, rounded to 90%
35.25/40 + 20% = 108.125%, rounded to 100%
Now let's do the same thing without the -4 penalty from twf, which would be an attack bonus of 64.
(64 + 10.5)/(target AC * 2) + 20%
74.5/(target's AC * 2) + 20%
37.25/target's AC + 20%
37.25/60 + 20% = 82.08%, rounded to 80%
37.25/50 + 20% = 94.5%, rounded to 95%
37.25/40 + 20% = 113.125%, rounded to 100%
Since each of these is rounded to the nearest 5%, the attack penalty from twf only made a difference when the AC was 50, and the result was a +5% chance to hit.
The big unknown here is mob AC. Now I don't know what range of AC various mobs have, but I do know that on all my main characters (links in sig for full build details) as well as my less well built/geared alts, I never have trouble killing anything. Which means if I am missing, it's not enough to make a difference in my ability to kill mobs and complete quests. This leads me to believe that mob ACs are generally not that high and an attack bonus of 60-70ish will do just fine for the vast majority of content.
The new to-hit formula essentially minimized the value of player attack bonus. This was done to make the game more accessible to new players. And the benefits of someing like oversized twf, the penalty from twf, or starting with a low to-hit stat (e.g. 8 strength) are basically meaningless now because minor increases don't change your final chance to hit by much, if at all.