Grand song that it is, Flower of Scotland was written by Robin Williamson as a lament. If we adopt a lament as our anthem, then we deserve all we get!
There are several songs (notably Scotland The Brave) that are eminently more suitable. We need a glorious feel to a song rather than a whinge against the English. To quote Flower of Scotland, those days are past now.
Portcheek Terrace, Kirkmichael South Ayrshire