It has less to do with "needing" a new uniform and is more about wanting a unique uniform or identity(the page I linked at the top of page 2 has text that boldly says "Identity Defined"). You'll probably never see any major changes to the Browns because they have a very unique identity. They're technically the second newest franchise and they specifically wanted that look because that just is how the Browns should look. Even with the Lions' new logo and new uniforms, they still look basically same because they have that identity defined for them. When a semi-casual fan watches Sportscenter and they see highlights from teams like the Packers, Bears, Cowboys, Giants, Raiders, Eagles, 49ers, and Chiefs, etc., they will probably be able to recognize them immediately. This isn't the case for a team like the Jags. Just look at these two photos:
The Jags and Ravens away uniforms are nearly identical. That same person watching Sportscenter won't be able to tell if it's the Jags or Ravens immediately. So, the goal here is kind of similar to what the Broncos did a little over 10 years ago. They revamped their uniforms and created a modernized look that has also became a completely unique identity to them.