The most skillful and entertaining shot in pocket billiards is the "two way shot".....one foul takes this (for the most part) out of the game.....and if you have to call your "safeties" it takes the two way shot COMPLETELY out of the game.
Taking the best out of something is usually not prudent....pool's not exception, as usual, it's the "sample example".
There's no better rules for 9 or 10 ball than "Two Shot Shoot Out" (two foul 9 Ball), this is positively true no matter how it's positioned. Pocket billiard's strength is showcasing strategy and creative expression, to take this out is like taking the frosting off the cake....it's still cake, but who wants to eat it?
'The Game is my Teacher'
I agree with CJ about two way shots being a great part of the game. Having to call a safe is not the way to go, IMO.
I played hundreds of opponents 'Two Shot Shoot Out' because that's the ONLY way the top gambling players (of all skill levels) would play.
The reason "two way shots" are important is a player like will roll out to them constantly....we'll shoot one, two, and three rail banks,extreme cuts (mostly off the end rail) and play safe at the same time....and if we happen to make it we'll also play shape on the next ball....time after time, after time, after time.
The main reason Two Foul is better than One Foul is the situation that sets up the strategic battle of the game is established EVERY TIME......it's more like chess, or poker where there's constantly a battle of wits.....this barely exists in One Foul.
Taking out this element by calling "safeties" is a huge step backwards.imo There's no question about it......everyone will agree if they've played 'Two Shot Shoot Out' under serious conditions. Buddy Hall and every great player of that era will say the same thing about the differences.....and they will be correct from experience not from opinion. 'The Game is Their Teacher'