As someone mentioned, I would not worry about the private thoughts of the instructors. In my experience, the reg force staff at leadership training establishments are extremely professional. They wont let personal thoughts like that affect judgement. Your evaluations while on the BMOQ are comprised of a series of PO checks. PO means Performance Objectives. Basically, a PO is a test, either written or practical. The BMOQ comprises a number of written and practical tests.
In terms of failures, in my opinion, the highest failure rates will come from the practical tests in the field. The BMOQ comprises of two components, the IAP (Initial Assessment Period) and the BOTP (Basic Officer Training Plan). The BOTP is field heavy. In that portion you will be expected to lead a patrol, lead a section attack, lead a defensive and be an overall competent field soldier. The small party tasks are the precurser to doing patrols, and the other leadership tasks in the field. The small party tasks take place during the IAP portion.
The patrol seems to be where people have the most difficulty.
I wouldnt worry about it too much though. The training is good, and you will be provided with ample training prior to being tested on any PO. As long as you put forth a solid effort, and dont lose composure while under leadership stress you should do fine.