The Esoteric Magus gives away a lot for what it receives in return. At first glance it may seem that the price is just too high. However with a 1 class dip the Archetype works quite well. Why does Esoteric work? It works because of style feats.
Ki/Arcane points with Perfect Style and Ki Leech
Being able to use ki as an arcane pool is powerful. When combined with the spell ki leech it gives an easily replenishable source of points to allow for continued use of powers like Accurate Strike. When using Improved or Greater TWF Esoteric get more bang from AS than standard other magus builds because of the additional attacks. The feat Perfect Style opens up an easy to obtain ki pool. This combo works best with an 18-20 crit weapon like a waveblade and Ascetic Style.
Ascetic Style
Unarmed fighting becomes a powerful thing when combined with ascetic style. One of the primary weaknesses of UAS is the poor crit range. Ascetic style removes that problem. To improve crit range to 18-20 try the new Waveblade. The other problem is reach but with a monk chained weapon (double chained Kama, Sickle &Chain) Ascetic style opens that option as well. All with full monk UA damage.
Big Hits with Dragon Style:
The option to focus on strength and big strength mod multipliers opens up from using Dragon style. With 2 dragon style feats the Esoteric can use x1.5 str mod from every attack, x2 for the first one.
Jabbing Style
Since the esoteric is likely using two weapon fighting, they will have a lot of attack so Jabbing Style adds a big bump to damage for builds that are not strength heavy.
The problem with most of these options is that they are feat intensive and the esoteric loses all of its bonus feats. Depending on the build, 1 lvl dip into fighter and/or 1 or 2 lvls into monk solve these feat issues. This makes esoteric a somewhat incomplete archetype but a powerful multiclass option. If the plan is to use Ascetic Style then Unarmed Fighter is a solid option. If you plan to use multiple style feats or advance Perfect style for more than the ki pool then the Monk Master of Many Styles is a good option. If using Dragon Style and Dragon Ferocity the unchained Scaled Fist Archetype works well.
See two of many potential samples below:
Build One
01 UnMonk1 [Scaled Fist] Class Feats: (Imp U.Strike, Stunning Fist, Dragon Style*), Human: (Power Attack), Artful Dodge
02 Magus [Esoteric] 1st lvl Spells (of note: Frostbite)
03 Magus [Esoteric] Feat(Two weapon Fighting)
04 Magus [Esoteric]
05 Magus [Esoteric] Feat(Dragon Ferocity), 2nd lvl spells(of note: Mirror Image)
06 Magus [Esoteric]
07 Magus [Esoteric] Feat (Barroom Brawler)
08 Magus [Esoteric] 3rd lvl spells(of note: Tactical Adaptation)
09 Magus [Esoteric] Feat(Improved Two Weapon Fighting), Arcana (Accurate Strike), should pick up Ki Leech wand around now.
10 Magus [Esoteric]
11 Magus [Esoteric] Feat(Wpn Specialization), 4th lvl spells(of note: M.Physique II, Paragon Surge)
12 Magus [Esoteric] Arcana:(Spell Blending Arcana to gain Ki Leech or continue using a wand)
Build Two
01 Fighter 1 [Unarmed] Class Feats: (Imp U.Strike, Ascetic Style: waveblade*), Human: (Power Attack), Artful Dodge
02 Magus [Esoteric] 1st lvl Spells (of note: Frostbite)
03 Magus [Esoteric] Feat (Two weapon Fighting)
04 Magus [Esoteric]
05 Magus [Esoteric] Feat (Double Slice), 2nd lvl spells (of note: Mirror Image)
06 Magus [Esoteric]
07 Magus [Esoteric] Feat (Barroom Brawler)
08 Magus [Esoteric] 3rd lvl spells (of note: Tactical Adaptation)
09 Magus [Esoteric] Feat (Perfect Style), Arcana (Accurate Strike), should pick up Ki Leech wand around now.
10 Magus [Esoteric]
11 Magus [Esoteric] Feat (Improved Two Weapon Fighting), 4th lvl spells (of note M.Physique II, Paragon Surge)
12 Magus [Esoteric] Arcana:(Spell Blending Arcana to gain Ki Leech or continue using a wand)