Replace SB? Nope. Both are based on squad sized combat, but both differ in details.
TotH is like Squad Leader/ Advanced Squad Leader/ Band of Brother /Valor & Victory Old School Tactical. Abstract combat with full and half squads and combat weapons based on made up data. You don't control each weapon of a squad. You
point and fire.
Squad Battles is based on a number of men and detailed weapons they carry. You can fire all small arms or say just your MG 42's. SB has more details of squads and terrain.
I like both games. TotH is like my Squad Leader board game in 1977. It's a good solo game.
If TotH had PBEM or MP, I would still pick Squad Battles all day long.
Ed