"Scripture says that God reserves His wrath towards His enemies."
There exists a debt of sin (against God who is holy) that requires payment (Romans 6:23; 1 Corinthians 15:56). No man in his fallen condition could possibly fulfill the necessary demands to make restitution. Thus, Jesus Christ took on human flesh so that the debt of sin could be paid off. He is without sin. An infinite debt requires an infinite payment.
Penal substitutionary theory in a nutshell states that God Himself paid the full debt for offenses committed against Himself. This view on the atonement cannot reasonably be deemed morally repugnant when properly understood. If we are to be saved from the sentence of eternal condemnation, then it is a logical necessity.
If people honestly want to be treated fairly by God, then that would mean He show us no graciousness and mercy at all for our sins. Moreover, those who argue that no court system on earth has ever allowed for substitution in any form for certain cases are mistaken. This source provides a handful of counterexamples:
"...during the Civil War, a man could substitute for another man to go into active service. Likewise, when someone owes a debt to the authorities, anyone can pay for it. So the concept of substitution is applicable in some settings."
Substitutes for rapists and murderers in our justice system are not authorized because we already know that such convicts will most likely continue in their folly. When we are in heaven, sin will be completely and permanently erased.
"In both forms of suffering there is pain and frequently, death. However, I can't find in the suffering of God's wrath, any indication of a resurrection. And that is the difference between the suffering of God's wrath and in suffering as God's children in imitation of Christ."
Jesus Christ raised the question regarding His position to James and John to stress humility. The disciples would indeed be "drinking of the cup" in the sense of being persecuted for His righteous name's sake. The suffering that Christ voluntarily underwent was unique as He made atonement for our sins. No one else has the ability to do that. This source explains that:
"In the Old Testament, the image of the cup can symbolize God’s blessing; however, in the majority of instances, the cup represents the Lord’s judgment and wrath on wickedness (Ps. 75:8; Isa. 51:22). Here in Mark 10:38, the cup has negative connotations, which means it represents the cup of divine wrath that Jesus would drink on behalf of His people to save them from their sin."
"And Penal Substitution is proven a false doctrine which contradicts the Word of God."
The above statement is just a subjective opinion. The Roman Catholic Church has not dogmatically defined a specific theory on the atonement of Jesus Christ. Consider this excerpt on Peter Kreeft and Tacelli’s views regarding penal substitution:
"I do not think the Church has ever officially accepted some explanations while rejecting others...but I don’t think, properly understood, the Church has ever condemned it.”
Robert Stackpole is one example of a Roman Catholic scholar who embraces penal substitutionary atonement:
"...what I have endeavored to show is that the "multi-dimensional mystery" of Christ's saving work, especially in His Passion and Death, needs to include (but is not limited to) the doctrine of "penal substitution": the doctrine that God in Christ, out of His merciful love for us, took upon Himself, in our place, the penalty due to our sins, so that, as St. Paul wrote: "Hence, now there is no condemnation for those who are in Christ Jesus" (Rom 8:1)."