I understand the concern, but hiding dkp numbers will not "solve" this. People will still talk to one another. If a item for a specific class comes up (as example), one of two things will happen: 1) People collaborate and give the item to one person for a minimum price 2) People will bid as much as they possibly want to spend no matter if DKP is hidden or not (may it only be to increase the prize for the person that will end up getting it).
But as the rules say, you do not pay what you bid. You pay "one over" the 2nd best bid - making this statement pretty much void.
Basically, hidden dkp promotes some kind of "black market" if you will where people start whispering to one another about bids on items that can come up from the next boss. Yes, they will also do it of dkp is know for everyone - but at least it is a more fair game. (i acknowledge that we are both using the argument "more fair" for our different points of view)
In the end: whatever... i will be fine with either way, just voicing my opinion here
Your opinion is appreciated and you bring up valid points. Thank you.