All of those are terrible ideas. Let's see:

Backlinks for replies

Superfluous, messy

Stickies

See above

Mobile theme/s

No way, mobile users need not to post

better admin panel

Unnecessary, admins should stay out most of the time

youtube embeds

Worst idea possible

spoiler tags

Meh

ban list for mods / ban message screen if you are banned

Privacy violation. No need to maintain lists of any sort, banning on textboards should be very rare