Rashi (22:2) writes that Hashem used the term “na”, please, in commanding the akeidah because Hashem begged Avraham not to fail so as to not provide the people of the world with an excuse to say this failure proves the first tests meaningless and Avraham and his religion are a failure. It is remarkable that people might even consider dismissing the rest of Avraham's accomplishments and legacy if he should fail to meet the demanding test of the akeidah, but we know that's how people are. As I commented recently on someone else's blog, a talmid chacham could spend years learning and teaching Torah and all that good can be undermined and dismissed if the individual makes even one strange comment that gets noticed and broadcast --the yotzei min haklal becomes the definition of the klal. Anyway, getting back on topic, I don't think Rashi here means to say that the only reason G-d wanted Avraham to succeed was l'afukei his detractors (as some interpret), but rather in addition to all the good reasons we would expect G-d should want Avraham to succeed the word "na" clues us into an additional factor at play here.
Rav Shteinman in Ayeles HaShachar raises the rather pragmatic question of how people might draw any conclusion from Avraham's response to the akeidah -- who knew about the test and who would know whether Avraham passed or failed? He therefore concludes that Rashi does not mean to say others will literally question Avraham if he fails, but rather the one blot on an almost-perfect record would cry out for correction. You don't get as much credit for the 99 successes as the blame you get for that one failure.
Rav Shteinman goes yet a step further and writes that all the previous successes were not true tests as they did not pose a challenge for someone on Avraham's level. The akeidah was the one and only true test of Avraham's character (I would note that the word "nisah", test, is used only here and not earlier in the Torah [see Netz"iv]), and therefore, success here was critical.
I want to contrast R' Shteinman's approach with that of the Arugas haBosem. The Midrash notes that the test of the akeidah and the first test which Avraham faced, the test of leaving his home, are both introduced with the words, "lech lecha". Given the similarity of expression, the Midrash seems to equate the two tests and asks which was greater. The answer -- the akeidah was greater -- is obvious and not nearly as surprising as the fact that a question and hava amina to think otherwise was raised in the first place. The Arugas haBosem explains that objectively speaking the akeidah is certainly the greater test, as the Midrash concludes. However, G-d's tests are calibrated to the level and ability of each individual. The test of leaving home may very well have been as challenging to an Avraham early in his relationship with G-d as the test of the akeidah was to an Avraham who was already mature in his religious development. It's not the objective accomplishment alone which counts in G-d's eyes; l'fum tza'ara agra -- its the effort and progress of the individual relative to their ability and gifts which count as well.
These two approaches are not mutually exclusive. We each have a task and goal for which we were placed in this world; whether we passed that test and did or did not achieve that goal is a significant question. But at the same time, achieving that goal may require overcoming numerous hurdles and obstacles, each of which drives development to the next stage and each of which is an accomplishment in its own right.