Some nice way to display decklists
Deckstats has a bunch of different formats you can use to nicely display decklists, I don't think any of them work on the boards. It can help especially if they have built in links to cards etc.
The other thing I think would be a nice feature is the ability to auto-highlight/link magic cards by name and some way to type mana symbols, numbers. I just think it looks nice on reddit/slack emoji replacement.