Please, add the possibility to copy additional attributes from methods to generated commands, as it is done for generated properties:

partial class ViewModel {

    [GenerateProperty]
    [StringLength(100, MinimumLength = 5)]
    string username;

    [GenerateCommand]
    [Display(GroupName = "<Commands>-", Name = "New...")]
    void AddNew()
    {
        //...
    }
}

Adding attributes to generated DelegateCommands, allows programmers to create attribute-based logic on commands. By example, to customise displaying of commands in the view.