For the main uniform, I don't like the shoulder boards, too dated, even by our standards, and it looks bad. I also don't like piping down the legs. A simple stripe would do, or a series of stripes or patterns denoting ranks. If you want to allude back to wet navy, you can also use rings around sleeves to denote rank.
I like the hat idea, even if it is only for the captain, it would look great.
I like the wings idea
I like the velcro idea but they should not be visible, otherwise the uniform looks cheap. A captain has to exude authority, not look like a car mechanic or a garbage collector.
Ties, I like them, but i think they would be outdated by 24th century and would look silly, just like those old ties look silly to us?? Either way, you can design a good uniform with or without them.
May be include gloves? They looked good on Romulans, plus they are very functional.
Germans had very nice uniforms back in the day. Here's Admiral Donitz, pretty cool. I think simplicity is important, don't overdo it. Regular officers should just have starfleet insignia, may be a medal or two, and rings and/or stripes for ranks.
PS I think DS9, Nemesis dress uniform was nice. The sharp angles of the jacket gave them an alien appearance, and there should be at least some alien influence in the design.