Arcane Weapon Enchant: Fire + Electric + Cold = Elemental Barrage. x2 if your weapon has another element too.
Then you also get Bane Blade eventually for +2d6 damage (and +2 AB).
Holy and Axiomatic will offer +2d6 too (possibly 4d6 vs Chaotic Evil - but you'd likely be giving up Elemental Barrage - which wouldn't be worth it).
Lethal Focus adds Int mod vs Flat-Footed enemies (you have Shatter Defences, right?). Or well, that Mobility 2 trick should also do the job.
As a Sword Saint you qualify for weapon Specialization - and that's up to +7 with Mythic Spec.
Crits will be much more reliable with Critical Perfection and will hit harder with Perfect Critical.
A Sword Saint has no shortage of damage.
Will have much easier time hitting tough enemies with Dimension Strike / Arcane Accuracy too.
I don't need shatter because trickster mobility 2 forces enemies to flat flooted when you AOO them after an acrobatic movement check. Just to be clear with the build's working theoretically : You move out of an enemy threat range with acrobatic movement turned on (which now gives you extra movespeed thanks to mobility 1), if you succeed at the mobility check vs enemy CMD, you make an AOO against them and it targets flat-footed AC (from what I have read, regardless of Foresight, uncanny dodge or other FF immunities) and regardless of your own reach. Another thing about this, is that when you succeed at the mobility check, the enemy doesn't actually execute the AOO, you just zip out of its threat range, get the AOO for free and the enemy's 1 AOO per round counter is still at 1.
Which means that in theory:
1) I don't need shatter defenses since I will attack only through AOO and they will all target Flat footed AC. AB isn't that scares since I get full benefit from ever ready (Mythic lvl to AOO attack and damage rolls)
2) I don't care about BAB progression except for the attack bonus concern (and early game concerns), since I will almost never Full-round attack past mythic 4
3) The combo Mobility skill, Movespeed and DEX modifier is everything to this build. Determines how many times I can attack while moving, whether I get hit or not. Hence the Dex build. Its not ideal vs archers without snapshot but I'll have companions to handle those.
4) I would never need to use a standard action, unless I cannot beat CMD with mobility checks, just keep on zipping. Having a good swift would be nice though and SS has that covered.
The sword saint is interesting I will look at it more. What I don't like with the elemental barrage route is that I probably need to take some ascended element feats? I haven't played around with elemental barrage so I don't know much about how to build melees around that. Currently on the rogue, all I
really need as far as mythic feats are concerned is Ever ready (since it's an AOO build) and mythic skill focus : mobility at M3-4 so I have space. Although I would love to get QoL stuff like rupture restraints in. Maxing out dex is important so I'd need to fit at least basic mutagen in. There is also the concern of getting class skills (I will probably go mobility 3 and trickery 2 with him so I have a good dispell for tough bosses) but I am sure I can figure out something.
Depends how you want to play. If you wish to play solo, the easiest way bar none to do the shield maze is to just give everyone who can cast arcane spells if they had ranks in an arcane school, levels in an arcane school and then spam magic missiles on absolutely every enemy. Since you will be ditching them all the moment you get out of the tutorial area, it isn't like it really matters that you butcher their class. If you are actually planning to run with companions, it is a bit more complicated since you don't really want to butcher their class.
Yeah I just want to go solo early for an exp bump. I won't go solo for very long. Maximum until lost chapel if I even make it there. Then I probably go with 4 man party, using companions I ignored on my first playthrough.