Thoughts on Warlock echoing blades skill order

I plan on changing my warlock to an

Echoing Strike build. Lets say the character will be level 75. Of course skill points will be limited. I plan to put one point in all the summon skills, one into Lethargy, 20 into

Echoing Strike, and 20 into

Mirrored Blades. This is where my question comes in.

Normally people would suggest maxing out

Blade Warp next because of the synergy with

Echoing Strike, but that synergy is only like 5% damage per level. I'm thinking it would be better and more damage to instead max out

Hex Purge (A skill I plan on using), and

Hex Bane next. So even if you don't have points for Bane, I'm thinking purge will still be more damage than investing in

Blade Warp. Then you invest in Bane because that's an additional 10% magic damage which is not only better than the 5% you get from

Blade Warp, but it's also good to have multiple types of damage.

What are some thoughts on this?

Echoing Strike Warlock feels less pressure to diversify his damage types because of the skill

Bind Demon. Once you acquire a demon that has the Cursed trait, nothing in the game can stay Physical Immune.

Hex: Purge and Hex: Bane add a good deal of damage, but honestly, adding more damage feels excessive once you've got a good enough 2-handed weapon. I might suggest investing into

Blood Oath for its safety factor instead. The skill both increases the health of your precious bound demon immensely and reduces the damage you personally take by venting a portion of it to your demon(s). Considering how critical it is to maintain a good bound demon (and dying kills your bound demon),

Blood Oath sounds like a better deal to me.

If you don't mind it, test your character with skill points left over once you've maxed

Echoing Strike &

Mirrored Blades. If it's not doing enough damage, look at your weapon. If it can't be improved further, then I would invest into

Blade Warp for synergy. If it's already the best you have, Hex: Bane or Hex: Purge for adding a second type of damage could be good. And if you are already doing enough damage (which I suspect) -

Blood Oath for safety and convenience would be best.

I changed to

Echoing Strike at lvl 35... Best choice of my play. It is so much better than the rest.
Echoing and Mirrored max out as fast as possible.

Blade Warp was my next.
I use the

Hex Purge mainly (get this maxed aswell) and only keep 1 point in

Hex Bane as itll gain more lvls and enough power to deal with 1v1 situations which feel slow. It is rarely, but sometimes boss kill is faster with it if you are not strong enough with the

Hex Purge.

Insight is a big plus to have before good mana steal.