What positions do we have to make improvements to this offseason?

It really doesn't matter.

Adding the best LT or DE won't make this team a contender.

To win anything of significance you need two things.

1. A top 5-10 QB (usually top 5 and mostly top 2-3)
2. A top 10 HC

The Saints have neither.

They have the worst HC in the league and a very average to mediocre QB with zero intangibles.

Against a trash schedule that was good for 9-8. Against a good schedule, that's probably a 5 win team.