Fascinate was broken, granted. But it also was very easy to break. The Pathfinder version is incredibly weak in all directions.
Um... what?
The only change is the save.
Number of creatures. The same.
Effect (no actions and -4 on check senses). The same.
One attempt per 24 hours. The same.
Potential threats allow a new save. The same.
Obvious threats break it automatically. The same.
The
only difference is instead of a save DC that goes up every level it goes up ever second level and there are far fewer ways of boosting the save.
As for three two round fights, at that point the Bard would probably be better off simply not using bardic music unless he's not going to do anything at all useful with a weapon. Giving up a standard action (i.e. your attack) is massive - and a 10% DPR swing per person isn't that much unless you have a big party/retainers or a seriously twinked out fighter, especially not as the damage output is back-loaded. Psyching your guys up before the fight, a rolling fight, or a battle chant for an entire encampment are a whole different story. (For what it's worth, three round fights are probably where it starts to become worth it).
At low levels, most fights are only going to last 2-3 rounds. And the bard, being super squishy with their 6-8hp, really shouldn't be getting up to the front lines, especially not before the fighter. Singing and then moving is a valid first round, followed by moving and attacking the second - allowing the more armoured characters a chance to get into position.
While the +1 attack & damage isn't much, at low levels you're not rocking a whole lot of attack bonuses, so the +1 to attack rolls might be a pretty nice increase. At higher levels, the attack bonus is less impressive but the damage bonus becomes more important as it applies to multiple attacks.
Regardless, the bard always had to give up their standard to sing. But in PF if they sing and suddenly the fight ends quickly due to a couple crits (or the fight being less impressive than expected) then they aren't stuck without their key class feature. They still have 3-4 rounds left.
What other changes hit the bard between 3.5e and PF?
Well, bardic knowledge is clarified. What did bardic knowledge do before? A bard "knows some relevant information about local notable people, legendary items, or noteworthy places."
While everyone treated it like bards could make a check for any other knowledge skill, it's actually pretty limited. Regions, gods, monsters, and historical events are not included (neither would be stories). It really just puts the onus of bardic knowldge checks onto the DM. There's no real guidelines or advice for what the check DC would be. Plus, very few modules every assumed bardic knowledge and so it was never really included.
PF changes it so the bard just makes knowledge checks untrained. So all the rules are right there. No special accommodation needs to be made for the bard.
Countersong is pretty much the same, but they also added a visual version (Distract) for illusions, which is a nice buff. While this does force bards to learn a second performance skill, their versatile performer ability at level 2 means they can ignore a couple skills.
Their spellcasting also got a bump, so they get 1st level spells at 1st level instead of 2nd. This is pretty sweet. And like all spellcasters, 0-level spells become at-will spells.
Their hit dice jump from a d6 to a d8. And their BAB and saves remain the same.
They still get 6+int skills. But instead of 24 + all Knowledges to choose from they
have 18+ all knowledges, meaning their skill points can go farther.
Plus at higher levels they get four more performances than the 3.5e bard, get the boost to inspire courage earlier,
