The software feels antiquated as compared to other IM platforms and we feel the UI could be updated for better user friendliness and experience.
Your UI enhancement requests should be very specific. Example. - Allow panes in the interface so that users can customize the view. The "panes" on the SW client and web client and mobile client should be independently managed [for obvious reasons regarding real estate on each device.]
And as the other person said - make your requests to Microsoft directly.