Let me review your review the way you have reviewed their redesign.
I find critiquing a design from the outside a little problematic. Why? You are not in a position to talk about whether a redesign achieves it’s aims, given it’s constraints, because you can know neither the aims nor the constraints from the outside. If we are to go ahead and attempt a critique given this limitation, we must do so with care and humility.
Accordingly, It is advisable to take Dropbox’s word for it, when they tell us the aim of the redesign.
As our mission has evolved from keeping files in sync to helping keep teams in sync, we realized our brand needs to change, too. Our new brand system shows that Dropbox isn’t just a place to store your files — it’s a living workspace that brings teams and ideas together. — Dropbox design team
In simple terms, design is all about reducing the friction between users and their goals. Design is not only software. There are various design systems around us.
Nowadays, companies employ design to reduce the friction between users & their goals and to convert visitors into recurrent users of their product. — Momoh Silm
As you can see, the aim of the Dropbox redesign is not to reduce friction or traction as you suggested, but to project their new identity. This is understandable, as this is only a redesign of the logo, typeface and colour scheme and currently does not extend beyond the login screen.
Logo and typeface, important as they may be, are not major contributors to friction or usability. The current redesign has not been applied to the core Dropbox app. As such, we will only be in a position to examine friction and usability when they apply the redesign to the actual interfaces that users interact with.
It looks like Dropbox is going about their Identity & Branding well, except that they’re not. Their concepts lack empathy, it lacks any personal connection with the users.
This is a strong claim as it seems like from all indications, users were a major consideration in this redesign. But I’ll let Dropbox speak for itself as they wrote about it here.
Finally, the criticisms on consistency and colour come from a recent trend in design of equating minimalism and a clean aesthetic with good design. Good design can be minimalist and clean or it can be bold and in your face.
Dropbox wants their brand to reflect their desire to be more than just a file storage system. In their own words they want “to show that Dropbox is an open platform, and a place for creation”. What you think about this strategy or their past failures is irrelevant here, the question is whether the redesign achieves what they set out to achieve, I think it does. Although, I give my modest stamp of approval with the understanding that I have no insight into their aims and constraints.