Not sure what you mean by "fluid", but if you mean the opposite of "static", that is, that PF2 characters are able to move about the battlefield more, then I'm all for it
For me, this was my definite experience playing in the PF2 playtest. Combats were by far the most fluid of any D&D game I've experienced. Three actions per turn combined with the big incentive to roll 10+ higher than your opponent and land a critical (plus the desire for that NOT to happen to you), plus moving opportunity attacks to a special thing some people do rather than a thing everyone does made a big difference.
Some typical rounds were:
• Move form behind cover, stab opponent in back, run off to new cover
• Hit opponent, move to new opponent, hit opponent
• Cast self-buff, move to enemy, hit enemy
The spell system, with variable effects based on how many actions you take casting, also makes for fun decisions: I can use a 3-action heal to heal everyone, but only Bob really needs it. Maybe I should move to Bob, cast a heal on him and then hit the opponent.
Raising a shield as an action is also really interesting. I recall once when a large sea creature was our solo opponent thinking I'd move in and double attack. When I saw it crit our other melee fighter on a roll of 13, I changed my mind -- move in, attack and raise shield!
4E is still my vote for the best tactical combat game, but PF2 is faster, simpler and so for a fluid combat style, it's a winner.