This seems to be a very subjective question to me.
Promoter holding is important but it does not prove to directly impact the company.
I personally feels one should see the pattern over last few quarters and years. If promoters are increasing thier share holding its a good sign (proves they are optimistic about future).
Regarding selling of shares , it depends on the amount of shares which is sold. One may need to sell the stock for thier personal reasons also. So one should see the proportion of the shares sold to the total share holding. then should make a logical decision. Example can be Selling of Shares by Kaveri seed promoters when they diluted last year around 7% stake.
Regarding Pledging of shares I stay away from the companies whose promoters pledge more than 25-30% of shares because even if pomoters have good intentions of paying back the loans and repay shares , there is always a risk of selling of shares by the lenders which can drastically reduce the share values and can lead to share price crash…