I think the media are giving Pochettino far too much credit for fostering a good squad atmosphere at Southampton and assuming that he'll be able to do the same at spurs.
When he joined Southampton they were already a tight-knit young group who had been through several promotions already, and he could hardly speak English anyways.
The atmosphere in the squad when he joins Spurs will be completely different and much less harmonious, especially on the back of Tim Sherwood.
As for playing style, Im not so sure Spurs have the personnel in midfield or attack to play a high-press, and much less so any defenders who are capable of playing effectively in a high line.
Solid move for Spurs though from a purely footballing perspective, but I wonder if he'll be given enough time to get his ideas ingrained. The move is more of a risk for Pochettino either way, but I suppose he sees this as his best chance of moving up in the league in the next couple of years given how defined all the other top clubs are now with their manager situations.
I think he could get 4th if all things go right (Lamela up-and-firing would be a start) but personally I can't see them getting any higher than 6th next year.