Post patch, a Knight Enchanter needs to actually alternate between casting spells and using Spirit Blade to make the most out of the specialization.
I would personally suggest low cost, decent damage or low cost high damage spells that have a large area of effect. This will allow you to keep the Spirit Blade topped up with charges.
Here are my spell suggestions.
1) Immolate. Either upgrade works.
2) Fire Mine. Go with Searing Glyph upgrade for now because Flaming Array does not consume barrier with Chaotic Focus passive.
3) Wall of Flames. Go with the Wave of Flame upgrade.
4) Fade Step. Either upgrade works.
5) Blizzard. Go with Winter Winds, though I would primarily use this for keeping Ice Armor up.
6) Chain Lightning. Go with Arcing Surge. You want to hit as many enemies as you can to charge Spirit Blade.
7) Energy Barrage. Do not upgrade this spell for the upgrade either provide a very limited elemental resistance or they reduce the damage of this spell.
8) Barrier. Go with Energetic Defense upgrade, it is the better upgrade for difficult combat situations.
9) Dispel. Either upgrade works with this spell.
10) Spirit Blade. Go with Amplified Blade. Defending Blade upgrade is useless because you have Fade Cloak and the shockwave damage is not good enough.
11) Fade Cloak. Either one works. If you want an aggressive playstyle, go with Decloaking Blast and if you want a defensive playstyle, go with Enduring Cloak.
12) Revival. If you want to pick this up, you can go with either upgrade but I advise going with Desperation only if you have "On Kill Health Gain" enchantments on your weapon.
13) Resurgence. One of the most useful Focus in game, in terms of utility. It effectively replaces Revival.
The other spells, are, in my opinion, not worth it.
For passives, there are the top priority ones.
1) Fade Shield. This is the defining passive of the Knight Enchanter.
2) Combat Clarity. Knight Enchanters now need to cast spells a lot more so you will need all the mana regeneration you can get.
3) Flashpoint. Dem' crits, so lovely.
4) Clean Burn. It is no longer that important for Knight Enchanters but it still is quite useful.
5) Chaotic Focus. One of the must have passives for offensive Knight Enchanters.
6) Conductive Current. The less mana you have, the more damage you do. What's not to love ?
7) Peaceful Aura. You are not a warrior so high aggro is unhealthy for you, especially since Spirit Blade is not what is used to be.
8) Guardian Spirit. This is essentially a shield gate.
9) Rejuvenating Barrier. You gain extra mana regeneration every time you have a Barrier up. Knight Enchanters are all about Barriers.
10) Mana Surge. In the event your Barrier goes pop, you get a free spell and a cold AOE.