My RPG group is made up of players who had all played either 2nd or 3rd edition before, where bards had a combat-bonus ability significantly different than what's in D&D 5. In both older versions, the bard was able to grant a combat bonus to all of its allies within earshot.
This was significantly changed for 5e, with bards instead being able to give their allies a "bonus die" which can only be used on a single roll. The bonus is so different from what everyone's used to that, so far, no one's actually used the bardic inspiration die to modify a roll.
Based on statements like this answer to "What changed between the playtest and 5e?", it seems like for at least part of the playtest bards had a significantly different ability. While we wait for whatever optional rule is (hopefully) in the DMG, can someone describe in broad strokes what the 5e "bardic performance" was like?