The revised action economy rules from Pathfinder Unchained refer to the monk's flurry, however it's not clear whether this monk is the regular CRB monk or the Unchained monk, or both. I assume that it refers to the CRB monk (because the rules described for the flurry are more like the CRB monk than the Unchained one), but it's obviously not clear, or how the Unchained monk would work with these rules.
The rules in different chapters of Unchained were made independent of each other, so they are definitely referencing the CRB Flurry of Blows. As for how the UC Flurry works with this... its up in the air.
The new flurry is better all around in my opinion,(with regards to the old system) since it adds nothing but additional swings at your highest attack bonus.
I'm about to implement the new action economy in my game, and one PC may actually select an Unchained monk. Seeing as that presses me to make a decision, I may have the flurry follow TWF rules in the new AE. Monks will be rather powerful, as having a high speed is very beneficial in this new system. Being able to move 50+ feet and dish out 4 swings will be nuts.
Also, a few other things to consider is how some swift actions -should- behave in the new AE. I'm namely speaking of the Ki point use for monks in this regard, where they can spend 1 as a swift to gain another attack. Ideally, that use should behave as a free action in the new system, otherwise it wouldn't make sense.
I am also implementing Stamina in my next go around. In case you are too, there are some other neat tricks monks will be able to pull off in the new AE. One that springs to mind is Medusa's Wrath. The combat trick would allow a monk to perform 5 attacks in essentially 1 act. (2 for flurry, 1 from Ki, and 2 from Medusa's Wrath).
So, assuming you have a lvl 20 monk (meaning an extra two attacks from flurry), how would the be placed? Both extra attacks together with the first attack? Would they have a penalty? I'm having difficulty coming up with a way which purely translates the flurry across without making it two powerful (e.g having three attacks at max BAB in one act) or weaker.
Like I said, it's up in the air. The way I would handle your level 20 monk is giving him two swings on his first and second acts used to attack. Since the new Flurry doesn't mention it behaving like Two-weapon fighting anymore, the -2 attack penalty probably wouldn't apply.
Using all 3 acts to attack would look something like this (only regarding base attack and Flurry): +20/+20/+15/+15/+10.
He could spend a Ki point, and get another in at +20.
That pretty much puts him on par with someone that has Greater Two-Weapon Fighting (6 attacks), but the monk still comes out ahead in 2 regards. He doesn't have a penalty, and his Flurry didn't cost him 3 feats.
Like I said, it's up in the air. The way I would handle your level 20 monk is giving him two swings on his first and second acts used to attack. Since the new Flurry doesn't mention it behaving like Two-weapon fighting anymore, the -2 attack penalty probably wouldn't apply.
Using all 3 acts to attack would look something like this (only regarding base attack and Flurry): +20/+20/+15/+15/+10.
He could spend a Ki point, and get another in at +20.
That pretty much puts him on part with someone that has Greater Two-Weapon Fighting (6 attacks), but the monk still comes out ahead in 2 regards. He doesn't have a penalty, and his Flurry didn't cost him 3 feats.
This is how I've run the unchained monk in my own games. My players like the revised action economy and our monk never complained about it.
It seems weird in that regard, because you're pretty much always Flurrying. But I mean, that's pretty much what every monk would want to do anyway in any system right?
I think my only minor deal with Flurry behaving like this is how much better off a Two-handed Weapon Monk is than anyone else. Since it doesn't behave like the old Flurry, you still get 1&1/2 Strength with Two Handed Weapons. That's 5 swings vs anyone else's 3.
I also couldn't help but notice the extra swing from spending a Ki point has to be an unarmed strike. It wasn't like that before...
So the main differences are:
Unchained loses an additional attack between the levels of 8-11, and 15-20, however does not receive a -2 penalty to hit at all levels?
so level 8 would look like this:
+6/+6/+1/+1 - norm
+8/+8/+3 - unchain
level 11 would look like this:
+9/+9/+4/+4/-1 - norm
+11/+11/+11/+6/+1 - unchain
level 15 would look like this:
+13/+13/+8/+8/+3/+3 - norm
+15/+15/+15/+10/+5 - unchain
and level 20 would look like this:
+18/+18/+13/+13/+8/+8/+3 - norm
+20/+20/+20/+15/+10/+5 - unchain
On top of that the normal monk's two bonus attacks count as offhand for the purposes of applying strength to damage?