The situation that came up was that we were fighting a high level orc warband (part of a larger orc settlement) - about a dozen orcs that were a good fight for 6 PCs levels 5&10 (we had two guest players doing a cameo with their 10th level PCs from an earlier campaign in the same setting), which included the chief of the orcs. After we had done some fairly major damage on the warband as a whole it was to one of the more powerful hirelings "we're going to kill the chief but we have no quarrel with your tribe. Help us finish him and we'll install you as the new chief." The DM thought this was reasonable - I pointed out it was an auto-save if it's not reasonable. The orc failed his save. But the DM said that it was too powerful, so it planted the seed but wouldn't change his actions during the combat.
Which made it useless, since we were fighting the guy. We were winning - a retreat at that point would have let them attack us while we retreated and stopped our progress. Definitely not worth continuing Concentration during combat at the cost of not doing any other Concentration spells.
I have to disagree with the assessment of the Mobile Flourish because it pushes them "up to" 5 ft _plus_ the number rolled on the die. So basically, it's added damage and disengage. So you hit them and do more damage and get free no-save pushing that allows for a disengage. If you like you can move closer to them again (which sounds dumb), but better yet, run away.
If you're against a single opponent, without reach, and you need to move - then it's decent. Though it's not "free", it costs one of your bardic inspiration dice.
Often Defensive Flourish can grant you a good enough AC against multiple attacks that mathematically it's superior (as in it saves more damage over it's length statistically) than avoiding a single attack of opportunity that may or may not hit.
It's a niche use. Eight HPs left and an Opportunity Attack will drop you and you need to get away is a great time for it - though at that point you might want to just take the disengage action and instead of risking missing. Pushing a foe into a hazard is fantastic use for it.
Ok, definitely not a "free" disengage per se. It may be a little more niche than the Defensive flourish, but still way more useful than Slashing.
I think I'm just trying to further justify/magnify the Swords Bard in my head as I really want to try it out.
But I want to add that I enjoyed this guide very much.
If you're against a single opponent, without reach, and you need to move - then it's decent. Though it's not "free", it costs one of your bardic inspiration dice.
Often Defensive Flourish can grant you a good enough AC against multiple attacks that mathematically it's superior (as in it saves more damage over it's length statistically) than avoiding a single attack of opportunity that may or may not hit.
It's a niche use. Eight HPs left and an Opportunity Attack will drop you and you need to get away is a great time for it - though at that point you might want to just take the disengage action and instead of risking missing. Pushing a foe into a hazard is fantastic use for it.