To reply to your questions:
Now my company doesn't issue any experience letter indicating the main duties of work expereince.
The job duties are an essentail element of the Letter of Employment. Did you include a letter of explanation for not being able to provide all the required information? And provide proof (e.g. email indicating your company will not provide the letter). NO
...
But I do have the application package submitted to the Consular Office which clearly lays out that I will be working as a .NET developer with NOC code 2174.
Did you submit this with your application? YES
...
There are other colleagues who have received PR with the same experience letter and application package combination. Now one of them suggested I haven't included a specific cover letter. Is that the only thing I am missing here?
A cover letter is not required per se, but if you omit a required document from the application, a written explanation is required.
You can try to appeal by sending an email, with either the required documentation, or the explanation, but the VO is not required to accept it. The burden has always been on the applicant to submit a complete and accurate application the first time, that is all the VO is required to evaluate. But sometimes, you can get lucky.
Now my company doesn't issue any experience letter indicating the main duties of work expereince.
The job duties are an essentail element of the Letter of Employment. Did you include a letter of explanation for not being able to provide all the required information? And provide proof (e.g. email indicating your company will not provide the letter). NO
...
But I do have the application package submitted to the Consular Office which clearly lays out that I will be working as a .NET developer with NOC code 2174.
Did you submit this with your application? YES
...
There are other colleagues who have received PR with the same experience letter and application package combination. Now one of them suggested I haven't included a specific cover letter. Is that the only thing I am missing here?
A cover letter is not required per se, but if you omit a required document from the application, a written explanation is required.
You can try to appeal by sending an email, with either the required documentation, or the explanation, but the VO is not required to accept it. The burden has always been on the applicant to submit a complete and accurate application the first time, that is all the VO is required to evaluate. But sometimes, you can get lucky.