It's true that a lot of teams has really strengthen their squad, which makes the league more difficult this season. Tottenham since to have started really well and Chelsea seems to be looking good too for the season.  Liverpool and Manchester City will always be a contender for the league.
I am really expecting an interesting season, but I just have this strong conviction that's its Arsenal's season, this be because they did not just strengthen their squad,  but they made the important signings that has been missing in the team for the last  three seasons.