Not considering oneself wicked: a response to Paul?

At Avot 2:18 Rabbi Shimon ben Netanel says: "Do not be wicked in your own eyes". Unsurprisingly there are many explanations of what he means. A superficially surprising and almost irrelevant comment on this part of the Mishnah comes from Rabbi Samson Raphael Hirsch, writing in the later part of the 19th century: 

The Mishnah does not mention guilt or intercession, so why does Rabbi Hirsch? 

Do not allow yourself to be taken in by the erroneous idea advanced by alien philosophies that man on his own must of necessity be crushed by the weight of his guilt, and that it is solely through the gracious intercession of another that he can gain control over evil and be delivered from the burden of sin.

On closer reflection his comment is both pertinent and relevant: its subject is Jewish conversions to Christianity. In the nineteenth century, the defection of Jews from orthodox religious practice took more than one form. For some, the less stringent demands of the Reform movement enabled them to combine a more relaxed and assimilated lifestyle with a sentiment of identification with their Jewish roots and some of their most cherished customs and traditions.  For others, advancement in society required not merely assimilation with the majority Christian culture but admission to it. Many accordingly opted for baptism and a complete change of allegiance.

Christianity is alluded to through Rabbi Hirsch's references to man being crushed by the weight of his own sin (i.e. to man being born in a state of sin and incapable of achieving his own salvation) and to the gracious intercession of another (i.e. to grace in the form of salvation through Jesus). But what connection is there between Rabbi Shimon ben Netanel and the threat that Jews might turn to Christianity over 1,800 years before Rabbi Hirsch’s day?

One of the earliest Christian apostles and a major source of the doctrine of original sin —the idea that man is born in a state of sin and requires salvation through the grace of Jesus—was Paul of Tarsus.  Paul, Jewish by birth and named Sha’ul, learned Torah with the first Rabban Gamliel.  

Sha’ul/Paul and Rabbi Shimon ben Netanel were exact contemporaries.  Would they have known one another? Very likely, if the Shimon ben Netanel who married Rabban Gamliel’s daughter was the same person as the Rabbi Shimon ben Netanel who authored the dictum under discussion here. If Rabbi Shimon ben Netanel had witnessed at first hand the splintering of the Jewish community under Roman rule and the growing popularity of the teachings of Sha’ul/Paul and those who thought like him, it would not be implausible that this Mishnah meant exactly what Rabbi Hirsch said it did—and its controversial content might explain why Rabbi Shimon ben Netanel was so carefully allusive and non-explicit in his choice of words.