Aurier and Doherty are better than Tomiyasu?
Bale showed up for 30% of the season so it's not a massive downgrade. Plus he only scored against weaker teams and a Leicester team on holiday. He couldn't be trusted against any decent opposition.
Aurier and Doherty at a similar level at RB to Tomiyasu at worst, likely better RB's than he would be especially for the upcoming season.
Still a lot of questions about Tomiyasu being able to play RB full time and tainge the step up from Bologna to Spurs. It would not be surprising if he took a season to adjust to the league and position, maybe longer.
Edit:
As for Bale we need those goals though. Lucas and Bergwijn haven't shown an ability to score against any team weak or strong on a consistent basis in the PL.