Are you for real? The more you post, the more I think you are troll who cannot possibly be serious. If you even had a basic understanding of the relevant mathematics, you would know that all of the items you listed are factored in. Let’s go through them one by one:
The overall average return is the average return per hand * the number of hands. When you are playing many hands, you are less likely to get a result where all hands win or all hands lose, but the formula remains the same. The chances of winning or losing all 4 hands would be relevant for computing variance from expected return, but we aren’t talking about variance. There is no need to look beyond average return per hand (* number of hands) for our purposes.
Actually the dealer has a greater chance of getting 21 because he hits up to 16 (in some cases soft 17 as well). He may get multiple attempts to reach 21. I hope you do not hit on 16 when a 6 is showing and instead stop after drawing a single card, so you only get 1 attempt. The dealer has ~10% chance of ending at 21 when a 6 is showing. If you hit only 1 card on a 10, then your only chance of getting 21 is drawing an Ace, making the odds ~1/13… less than 10%. Of course the chance of getting 21 is factored into the computer simulations used to evaluate expected return.
Of course he takes the doubled bet size into consideration and is not simply matching odds. Only a complete fool would ignore doubling your bet on a split when computing optimal strategy or expected return. It did not just slip the mind of every blackjack expert in the world. A multiply by 2 or 4 was listed every time in my calculations, sometime in bold. Yet you keep bringing this point up over and over again… refusing to acknowledge that the increased bet size is included in calculations.
Splitting 8s on a dealer 10 is not a big advantage, but there is a slight overall benefit to splitting (including the doubled bet size in calculation, of course)… as the average loss per hand is more than cut in half. I just ran a sim on splitting 8s and got roughly the same numbers that are listed on Wizard of Odds site. Wizard of Odds is certainly not the only expert to recommend this. It is a virtually unanimous conclusion.
Statements like this make me think you are a troll and cannot possibly really believe this nonsense. If you truly believed what you are writing, you must have realized that you are not skilled at math at some point in your life. Perhaps trolling is why your user title says “Probation”.