The difference between SA and Bloodmoney levels come from the fact that almost every area in SA is an inherently hostile area where you'd get shot if you get seen without a disguise, this is what the Colorado level was like, whereas Bloodmoney levels are more free form and have a lot of public areas where you blend in and work around the crowd. The least liked level in the new Hitman games is the one that's most similar to Silent Assassin i.e. You are also very rigidly restricted to your disguse's role in SA. Silent Assassin also has dated mechanics like the moment you start jogging you risk losing cover, whereas in the newer games you may attract attention but it won't blow your cover to a point where they start shooting you. But every level in the new Hitman games draws from the Carnival, Hospital, Casino, Wedding, and the suburban house mission from Bloodmoney. You won't really find level in the new Hitman games that are like Silent Assassin's levels.
There's a reason the new Hitman games, which are obviously successful, use the Bloodmoney template and not Silent Assassin. Hitman 2 SA really isn't better than Blood money.