The fandom has mixed opinion on the whole ace/sabo thing. Some people like sabo, while some people don't like the character.
To be honest, i also don't like sabo as a character. As some people had said, sabo just seems like a replacement figure for ace (brother figure with even the same DF). I just feel that diminishes the impact of ace's death for luffy (luffy losing his brother). Personally speaking, i prefer if ace just continues to live on and also joins the onigashima fight. Luffy doesn't have any character development any way since the timeskip. Ace was introduced back at alabasta and portrayed to be above luffy in terms of power. It is intriguing to see luffy and ace in the same arc finally on the same level, fighting against the invincible yonko.
To be honest, i also don't like sabo as a character. As some people had said, sabo just seems like a replacement figure for ace (brother figure with even the same DF). I just feel that diminishes the impact of ace's death for luffy (luffy losing his brother). Personally speaking, i prefer if ace just continues to live on and also joins the onigashima fight. Luffy doesn't have any character development any way since the timeskip. Ace was introduced back at alabasta and portrayed to be above luffy in terms of power. It is intriguing to see luffy and ace in the same arc finally on the same level, fighting against the invincible yonko.