1. none of recommenders will ever provide 'bad' feedback otherwise I would not choose that recommender and given that even in US, many rec. letters are firstly written by applicants and only after that (if ever) edited by recommenders, we can not expect any 'objectivity' here
True Dat! Buuuuut there are good recommendations and there are friggin AMAZING recommendations. And usually the difference is that the recommender is REALLY excited to help you out and participates in the process to make the recommendation even better.
2. what if my college mates might provide better examples of my leadership/charity experience or business-related traits than my clients?
It doesn't matter. They won't be worth anything.
3. many consultants point out frequent mistake that packages overconcentrate on work experience. Don't we make same mistake when choose current supervisor + peer colleague rather than current supervisor + college mate who knows me well for many years (not only in past but also in present)?
I don't necessarily agree with the first statement. So, no, not really.
4. don't my CV + job description essay + recommendation from current supervisor (who knows me for years and since the first day of work in the last place) say enough about my professional background. Will a recommendation from a colleague add much here??
No. A recommendation is not read for the information as much as it is used to gauge how your management feels about you. Yes, everybody gets good recommendations. But no, not everybody gets stellar literary works of art written by VIPS (but some do)
5. I do know cases in which the second recommenders were friends and even wives/husbands/mother(!) and that was not a deal-breaker though I don't know the statistics of unsuccessful applications. seems that alone it's not a factor
So do I, but only when there's a good reason (usually family business), and then usually candidates explain the reason and it makes sense to the Adcom. After all no one is going to throw away an application of a candidate from a good strong family business just because their uncle wrote the recommendation!