[PF] Mythic Game build questions.

[Omni77]

So I am playing Mythic pathfinder game with a few of my friends and I tend to get waaaay into making builds for characters. At the moment my character is a 5th level Dex-based Tiefling Magus Kensai/Bladebound/Fiend Flayer and I am Mythic Tier One. So after doing all the research I have found a build that I like. Basically the end result with be Dimensional Dervish+Mythic Whirlwind attack. The Debate about Dimensional Dervish+Whirlwind attack has already been had here (http://www.giantitp.com/forums/showthread.php?272482-PF-Dimensional-Dervish-Whirlwind-Attack). So I am sure the combo works as I imagine it.
The rules for Mythic Whirlwind Attack: Prerequisites: Dex 13, Int 13, Combat Expertise, Dodge, Mobility, Mythic Combat Expertise, Mythic Dodge, Mythic Mobility, Mythic Spring Attack, Spring Attack, Whirlwind Attack, base attack bonus +4, 5th mythic tier.
Benefit(s): When you use Whirlwind Attack as a full-round action, you may make all your attacks from a full attack action against one foe, and one additional attack against every foe within reach. If you expend two uses of mythic power, you may make all your attacks from a full attack action against every foe within reach.

By Expending a Mythic power I now get to make a magus spell combat against every foe within reach. Which as far as I can tell is very very good.
The only problem I am having with the build is its very high cost. The build will turn on at level 15 and Mythic Tier 5. So I am basically being very sub-optimal for those levels and tiers, because I need to sacrifice almost every feat and path power to this build.
My Build(feats):
Level 1 Feat: Weapon Finesse
Level 3 Feat: Dodge
Level 5 Feats: Combat Expertise/Mobility
Level 7 Feats: Intensify Spell (Shocking Grasp)
Level 9 Feat: Spring Attack
Level 11 Feats: Whirlwind Attack/Dimensional Agility
Level 13 Feat: Dimensional Assualt
Level 15 Feat: Dimensional Dervish

Mythic Tiers:
Tier 1: Dual Path(Champion/archmage), Extra Mythic feat(Mythic Weapon Finesse)
Tier 2: Impossible Speed
Tier 3: Mythic Dodge/Extra Mythic Feat(MythicCombat Expertise)
Tier 4: Extra Mythic feat(Mythic Mobility)
Tier 5: Mythic Spring Attack/Extra Mythic Feat(Mythic Whirlwind Attack)

So here are my Questions:
Q1: Is this build worth it, according to the damage numbers? Math wise how much damage will I have sacrificed just to be a Teleporting Full-attacking God at level 15. From the numbers I got at level 15 my build does more damage as soon as there are more then 1 foe and gets more ridiculous the more enemies there are. But by no means am I an Expert at Pathfinder or magus builds as this is my first campaign playing pathfinder.

Q2: Is this build worth it, according to how useful my character is? I know this is a more opinion based question. What I am asking is if it is worth it for my team if I go for this build. So far I am the primary arcane caster for my team, we have a few divine casters as well. Also as far as damage, my character is one of the more optimized so I tend to be a main damage dealer as well.

[Ninjaxenomorph]

Having played several magi, and planned extensively for a mythic one, do you really need to be dex-based and go for the Mythic feats? It might be better if you just go for Dervish Dancer, though I can see the desire for an exotic weapon. I'd say that Whirlwind Attack doesn't quite pay off for someone without reach, but there are spells to counteract that at least. However, I don't think its worth it. It would be interesting on a Whip magus build, but that would be extremely feat intensive.

[Omni77]

I have been playing since level 1 and so my character is kind of set in a Dex based build.
The reach can be fixed with getting lunge next time I get a feet or casting long arm or wearing long arm bracers.
I don't think it would be possible to build a whip magus along with my build. If you look at my feat list you can see it is practically full from the feats required for whirlwind attack.
Also don't forget the build is mythic whirlwind attack+Dimensional Dervish, that is a Full attack action to every enemy you can reach by teleporting a distance up to double your speed. I don't really need reach to get to my enemies. I do want reach to stay out of my enemies range.

Also I don't see any problem with a dex based build. With Kensai and Canny Defense my AC is going to be as just as high as plate armor which I believe I would want if I went str build, also it is all dodge AC which will apply to my CMD and Touch AC as well. I do not know if there is any way to get my CMD and touch AC that high without pumping a bunch of feats into it.

Of course as always I don't claim to be an expert I definitely want any insights into the STR build that I do not know about.

[Ninjaxenomorph]

I prefer STR magi, just easier to play. Never played a Kensai, though, but I understand the dex build. I just don't think using all your path powers on feats are worth it, considering how many amazing path abilities there are. Mirror Dodge is a fun one, as are many Archmage abilities. However, should you go down this path, there is a Champion ability you should know about:


Sweeping Strike (Su): Even when you're swarmed, your foes are not safe from danger. Whenever you could make a full attack, you may instead make a single attack at your highest attack bonus and apply the results to all opponents within your reach. Roll damage once and apply it to all opponents hit by the attack. This attack can't deal precision damage. If the attack roll is a critical threat, choose one target you hit and attempt to confirm the critical against that target.

That is including Spellstrike.