我覺得你開頭就有問題。
什么叫“步入正軌”呢……
中國政府、兩岸人民，甚至臺灣政府都不會認為是步入正軌……
前者有各純正官媒社評，中者有PTT、天涯等網絡平臺。
你論證“統一”不是必須。
關于第一點。
Updated: Years that China is united by Han Nation
Although some dynasty still exists, if China is not a whole part, years are
not counted.
Qin=From BC -221 to -209=12 (Acutal life: 14)
Han=Western=From BC 196 to AD 8=204 (Acutal life: 210)
????????? Eastern=From AD 36 to 190=154 (Acutal life: 195)
Jin=Western=From AD 280 to 290=10 (Acutal life: 154, including Eastern)
Sui=From AD 589 to 612=23 (Acutal life: 37)
Tang=From AD 628 to 859=231 (Acutal life: 289)
Ming=From 1382 to 1628=246 (Acutal life: 276)
PRC=From 1949 to 2016=67 (Acutal life: 67)
Total=947/2237=42.33%