I've heard often - especially from rabbis and in books that deal with shmirat ha'eynaim and shmirat ha'brit - that a powerful yetzer in these fields shows one has "כוחות חיים עצומים", which I guess would roughly translate as "strong life energies"(??). I've never understood what that meant. In what would I, someone who struggles a lot with this stuff - be different, in a positive sense, from someone who does not struggle as much or at all with this stuff? Yetzer Ha'min is what allows us to procreate, but presumably both I and Ploni Almoni - who does not need assistance from sources like GYE - could procreate. In essence, it feels as though I drew the shorter straw when Hashem was handing out middot. So, does anyone have any idea what's the point of having a powerful version of this yetzer?

I always thought of this as a personal trainer. If the trainer sees that his client is very coordinated, built well, and is driven, he will push his client far harder than he would another person. The extra push will help the client channel his energies and natural tendencies into better results. He will get stronger and develop better than if he just went to the gym and lifted a couple of weights and ran a couple of miles.
The nimshal is like the Gra says that one who struggles in a certain area has more potential than others to perfect that middah.
Your כוחות חיים עצומים aren't there to help you procreate, because you just like Ploni Almoni can do the job just fine. Your כוחות חיים עצומים are your own clue that Hashem sees in you the ability to flex and strengthen your כובש את יצרו muscles in a way that no one in the entire world (including your GYE family) has ever been able to do. Because of our own unique experiences and life settings our struggles are all individualized (even while similar) and the outcome is thus individualized as well.
I'll throw this in for fun, if it's not up your alley just ignore it:
The Ba'al Hatanya says that one who struggles with temptation and overcomes it knocks down the sitra achra and thereby reveals Hashem's glory in a way that is so much more powerful than  tzaddik's avoda. The reward for doing this is obviously very large as well. How fortunate we are that Hashem is צורי ולא עולתא בו and set us up with opportunities galore to rise above, to serve Him, to elevate ourselves and the entire בריאה!

הצלחה dear friend!

Hyr wrote on 02 Jul 2021 08:38:

I am no expert in the kabbolo approach. But I think their point is based on kol hagodol meichaveiro, yitzro godol heimenu. basically, if you have strong taives, that proves you have great potential. 

Nu, nu. Maybe yes, maybe no. 

Reb Tzadok of Lublin writes, “Kol adam yesh lo chemda – Every person possesses an inner desire.” It may be for money, physical pleasure, honor, or a variety of other pursuits. “But one should know,” says Rav Tzadok, “that these desires are not bad. Because within your most difficult nisayon (test), blessing in your life is hinged directly upon. That very desire you have, which was given to you by Hashem as a challenge, is the very key to blessing.

Someone who refrains from looking where he shouldn’t or holds himself back from saying something is directly infusing beracha into his life. In Dovid HaMelech’s mind, the key was to take the biggest thief and get him to turn it around.

The Satmar Rebbe zt”l would talk about the concentration camps and how people who had lost their lives and children rebuilt themselves. He said, “You have to take the pain, and instead of using it to be angry, convert it to beracha. Take the despair and convert it to hope.” He then would start crying, and everyone would follow with crying themselves. They then would calm down, and the Rebbe would say it again, and everyone would start crying again. When you left, you felt like you were washed in and out. It is the power of taking your weakness and struggle and turning it into your biggest source of blessing and strength in life. And we all can achieve that.

One of the other reasons that Hashem makes it so hard is not because He is looking for mighty warriors, but because He wants us to admit we can't do it without Him. He wants our broken heart, not our super-strong-will-power. All He is waiting for is a sincere prayer from the heart. "Father, help me. I can't do it. I need you. Without you, I am lost".

Another way to explain it, this challenge comes from a longing, a deep emotion and yearning for something, a "Ahava" that has its scource in "Ahavas Hashem" and is being misdirected and falsely interpreted. Therefore when this yearning is channeled in the right direction there's great potential for growth and creativity. 

As an aside we have conditioned ourselves to see these challenges, as well as other addictive behaviors, as failures, however when drilled down they are very much pointers to growth opportunities, where the soul is crying out in pain about something, and with the right tools we can utilize a moment of struggle to find these cracks and try to fix them. 

Basically this opportunity to overcome such difficult challenges enables you to become great. And even if people don't realize its greatness, Hashem knows and it makes you rank very high. But it's very hard to do. But that's why it makes you great