In Xanathar’s Guide to Everything a new subclass for Bards is introduced: the College of Glamour. This subclass has a new ability called “Mantle of Inspiration”, description follows:
At 3rd level, as a bonus action, you can expend one use of your Bardic Inspiration to grant yourself a wondrous appearance. When you do so, choose a number of creatures you can see and that can see you within 60 feet of you, up to a number equal to your Charisma modifier (minimum of one). Each of them gains 5 temporary hit points. When a creature gains these temporary hit points, it can immediately use its reaction to move up to its speed, without provoking opportunity attacks.
The number of temporary hit points increases when you reach certain levels in this class, increasing to 8 at 5th level, 11 at 10th level, and 14 at 15th level.
I have been running a Glamour(ous) bard in my level 5 campaign, and there seems to be balance issues with this ability. As a bonus action, for 5 rounds, the other 4 PCs in my party get 8 temp HP, and have the option of moving around the battlefield for the low cost of their reaction.
To me, the temporary HP amount seems unbalanced. Each turn (again, as a bonus action), I am able to dole out 8 temp HP. This is about 15-25% of our current PC health pools. I understand that characters must choose one temp HP source at a time, but our combat scenarios usually result in most members of the party taking damage each round anyway(due to ranged abilities and fast-moving opponents).
To me this almost completely overshadows normal Bardic inspiration, and thus lowers the interesting choices my character must make. Am I overstating/overvaluing Mantle of Inspiration?