It is indeed something that is really bothersome. as you write about those who are less committed. Actually R' Tropper's approach attempts to remedy that, by raising the standards of commitment of the convert. This is the reason why many Rabbis (like Rav Reuven Feinstein or Rav Shmuel Kamenetsky support his efforts).In such cases, one can understand that they earn to some degree respect, as (those who) transform their lives with some difficulty.
It happens that the Beis Din which I converted through is a well respected, accepted Beis Din with very high standards (Bli Ayin Hara). However, creating higher standards does not necessarily bear a stronger connection, commitment, and love of Torah within the individual conversion candidate.
Those feelings and commitments are something which exist in the person or do not, can be roused or can’t be – but in my opinion they cannot be forced upon the person or implanted in them. You could say that higher standards weed-out people who are less committed and serious, who are lacking these internal convictions, and perhaps this is true in some cases. However, if someone has an ulterior motive that is strong enough, it also could push them through a rigorous geirus process.
I do not believe (at least from what I have witnessed from the people I have seen go through conversions) that higher standards make for a better Ger. There is a lot of change involved in a conversion. It is not as simple as learning how to keep Shabbos and kashrus…. A Ger needs to completely resocialize themself to a different culture and lifestyle. You don’t learn all the social norms and nuances which make the Jewish people as a community so unique and JEWISH by taking a shiur on Kashrus.
Conversion should be viewed as a holistic change for the person. It is not just a change in halachic status from non-Jew to Jew; from not keeping Shabbos, to keeping Shabbos. In my opinion it takes a high commitment and drive for an individual to properly integrate and join the Jewish people successfully, and holistically.
All I am trying to say is that higher standards, although necessary, should not be viewed as some sort of panacea for preventing poorly integrated, insincere or wayward converts. It’s not a year or two year course in Orthodox Judaism that create well integrated, committed Jews; it’s an internal conviction and drive toward living a life dedicated toward Avodas Hashem which continues to drive that individual long past the geirus process is finished.