I think I'd call auctions and banking "advanced economy" and slate that at 1.1+ as a basic MUD needn't have these things but moreso because they can be kinda mud-specific.

Instances is also an idea that crossed my mind, but I was hesitant to address it. (Edit: Link). If we want to move forward with it, I'd push for 1.1 and beyond.

Custom prompts fits with the 'settings' theme of 0.5.  This is pretty minor/easy and needn't be called out in the roadmap.  Not sure what you mean with colors; users can already cause color changes stuff with their communications and such.  (I don't think we sanitize user data yet though, to prevent malicious usage.)

Aliases/macros would fit for 0.5. (Fortunately it should be a simple matter of ripping the command out of the project if the MUD admin is opposed to them rules-wise, etc.)  Also pretty minor.