Filtering is a nice addition but relative dates are missing, i.e. you can't set a filter to show items with a due date of 'today' or 'tomorrow', You have to specify an actual date. Relative dates would allow for the creation of a filtered list in items due today where today changes as the week progresses. I see this as a pretty significant omission in an app that can be used for managing task lists.
Could the good folks at Omni please let me know if this is something you plan to add.