I would say the dropped points were rather freakish, and actually Spuds are our biggest threat. The Newcastle game had the worst penalty decision of all time go against them (they were also really rusty at that point having had no proper pre-season), and the 3 they conceded against the Hammers was as bizarre as our implosion against Villa - I wouldn't expect to see either repeated too frequently. Spurs are right in the mix I'd say (depending on injuries).
I also think Spurs are the biggest threat this season. Man City are looking like they are in a transition period so I'm not convinced they'll compete consistently.
I put a high amount of weight in the manager as it's a very complex job, especially in their role in creating a performance mindset and maintaining that level for a sustained period of time.
Mourinho clearly has the most experience in this regard (excluding Klopp and Guardiola). He seems to have a cycle where he is in the right frame of mind to get teams playing, which seems to crack after about two years. He's currently looking like he's in his happy place, and I can see Spurs doing very well with a well balanced squad with some very good players in key areas.
Lampard is very inexperienced and will find it difficult to maintain the levels of performance in his team over the season.
Time will tell.