In playing Final Fantasy V with the FF1style party and then several solo single-class characters, I really started to appreciate the gameplay style created by job restrictions. The power job combos (Spellblade + X-Fight, Quick + X-Magic) are the same every time; the game is indeed much more interesting when you have a new or underpowered job that needs to find its own answers.
And in playing my White and Red Mage games, I had referred several times to the report of Spoony the Bard for advice. A recurring plan for both White and Spoony was to run a boss out of magic points by endlessly healing or hiding. There were no fewer than twenty boss battles that Spoony won the chickeny way. This seems like such a cheesy solution, taking advantage of the dumb AI who will endlessly fail to cast spells, unlike player characters who will do something else or quaff an Elixir. And Spoony's adventures read a bit unsatisfyingly at times; he relied on Hiding so often and really didn't use his songs all that much. Songs are of course much better when they're buffing four characters instead of one, and should be the central feature of the Bard class rather than Hide.
Also in the wake of my solo White Mage game came up the issue of party headcount. Sullla commented and I agreed that once you know the bosses and mechanics, FF5 is almost laughably easy with four characters. Even death and stone spells are no more obstacle than Mini or whatever, just whip out an item and keep going. Would a full four characters make for any kind of challenge even if assigned to one of the weakest jobs permanently?
I've got my variant. Four Bards. Hide not allowed.
That will fill all those goals: compel a group of Bards to win everything legitimately, see if there's any way to make challenge out of a full party, and bring Songs into the spotlight both as the bards' remaining real tool and by buffing a full four characters instead of just one. Sullla commented that the defining trait of bards in the FF universe is to be weak and irritating... except in FF5. These bards shall be noble and brave.
Naming the lead bard was easy. Besides Final Fantasy 1, my other favorite RPG as a kid was Ultima IV: Quest of the Avatar. Iolo the Bard is well known as a stalwart companion of the Avatar across several Ultima games and a solid playable character in his own right. And in a cosmic coincidence, Wikipedia says that the name Iolo derives from a Welsh form of the name Edward. Completing the full circle back to the Final Fantasy bard universe - how cool is that!
(Hmm, I should check out Ultima IV for variant potential sometime. I wonder how different the history of video RPGs would be if Ultima 9 had been the blockbuster Playstation-selling mass-market-penetrating title and Final Fantasy 7 had been the overbudget overhyped overdelayed disaster? Would we be playing nostalgic variants now of the early Ultima franchise rather than FF games?)
Read the tale of the Brave Bards.