Yes. There are exceptions of course. For instance, if you’re unsure or basing your opinion off of limited information. But we often use those qualifiers when we’re afraid to take a stand.
This example works better without “seem.” You should have a definite opinion of someone you’ve worked with for seven years.
She seems smart. I’ve worked with her for seven years.
She’s smart. I’ve worked with her for seven years.
Here’s an example where “seem”makes sense. It’s difficult to form a definite opinion from reading a resume.
She seems like an expert. I’ve read her resume.
She’s smart. I’ve read her resume.