Most players don't have the postflop ability to take the "optimal" line out of the blinds. So the optimal line for one player may be different from another player's even in the same situation, if their postflop abilities differ.
Exactly. That's why it's important to know your own limitations, and adhere to them, while at the same time, working on improving them slowly. It's more optimal in a 6-max game to play 28% or even more of your starting hands on most tables, but it won't be if you're not playing them well. That's why most people will tell you to play tight as first as you learn and observe the game. You walk before you run.
I have a ton of issues, and have had them for many years with a lot of video training sites, that teach their students to flat X range against someone's Y range because it will keep their weaker range in the pot and not push it out. Yes, this is absolutely correct theoretically, but what about the rest of the hand? If you should flat A9o from the BB against someone's open button because it will keep their weaker Ax range and Kx and below range in, it will do that. However, if you're not comfortable turning your hand into a
bluff, or knowing how and when to call down often enough, then you'll be giving away money considering that you're going to flop a pair less than 30% of the time on the flop.
Initiative is going to be key in NL poker until you understand the nuances of the game, and you have such things down to a tee like:
1) Bet sizing
2) When to profitably turn your hand into a bluff
3) How to induce your opponent to make the biggest mistakes possible
4) Read your opponents game plan, and know how to think 1 level ahead of them
and so on...
Until that point, strategies like 3-betting a hand such as A9 will make it more profitable, especially at micro and most small stakes games. You can c-bet on most boards, and force your opponent to have to make a hand or float you in a bigger pot.