#2 Multiple sources of goals
Harry Kane has been Tottenham's top scorer every season since 2014/15, registering in excess of 20 goals every season for 5 campaigns running now. Eriksen brings in close to 10 goals if not more on average every season as well. Son has now joined those ranks contributing his cool 15 to 20 goals a season as well.
This Spurs forward line has seen great cameo goal scorers such as Dele Alli, Nacer Chadli, Erik Lamela, and last season Lucas Moura. Spurs are able to consistently ensure they have 4 or 5 different goal threats from open play because of their fluid style of playing.
Crucially though, their Achilles heel for a while had been an inability to win without Harry Kane. Last season, they demonstrated their ability to overcome that particular obstacle, winning 6 out of the 10 games they played without the English striker. Son, and Moura have both borne the mantle of goalscorer for Spurs and found that they carry it well. Of course, when Kane is available, they're just as deadly combining with him.
It makes Spurs a deadly opponent to face, especially when they show the grit and mental fortitute to pull off a comeback like they did in last season's Champions League semi-final against Ajax. They're going to be raring to go this season.