Can't "blatantly best options" make it impossible to implement a lot of otherwise reasonable PC concepts? Say your concept is "competent class A with some minor quirk or odd background" and player X is playing "class A or closely related class with optimum choices". If player X's character almost always outshines yours, then isn't a major part of your concept is effectively removed? Are you actually a competent thief/fighter/cleric/mage if the party would never want you to do the thievery/fighting/clericing/magicking?
No. Not if you're comitted to playing your PC's concept. IMHO, the abilities a PC gets would be dependent on what the PC would choose not the player playing the game.
So, if my concept is "fire mage"- an utter and total (high-Int, low-Wis) pyromaniac arcanist- the fact that Sleep, Magic Missile, Lightning Bolt, etc. are out there won't really impinge on the character's psyche. He probably knows that there are more creatures out there that are resistant or immune to fire than any other energy type, and that doesn't matter to him, either. He wants things to see things
burn. That which he can't burn...well...he'll think of something else if & when. Besides, isn't helping you out what friends are for?
Sure, "competent class A with some minor quirk or odd background" is the way some people design PCs, and there is nothing wrong with that. I've been happily playing alongside some guys who play like that continuously since 1998. But it's less a solid
character concept and more of a character sketch. (And I
do realize that you were presenting it on the fly as but an example.)
I'll even give you a real-world example. If you want to be an entertainment lawyer in the USA, your odds of success are best if you live & practice in LA or NYC. Other cities matter, too, but those are the big entertainment hubs. Those would be the optimal choices.
Well, I'm an entertainment lawyer who lives and practices in Texas...and
not Austin, either. Odds are good that you'll never see my clients on TV or buy their music. So it goes. I still rendered valuable service to them, nonetheless.