It is opinion. The only thing we know for sure is that their are offers and bids in the high thirteens right now. Everything else is opinion. Value is what a willing buyer and seller agree on.
If only we knew for sure that those were the real bids/offers, and not the market makers themselves trying to maintain a certain profit level by simply massaging the numbers inside their database. Do you really have trust in the unregulated market makers?
If I want to buy right now, I know what I have to pay. If I want to sell right now, I know what I have to charge. If the volumes are high, the price will move to the next best offer/bid. You are right that the market depth chart is not completely reliable, but for small amounts, it doesn't hardly matter at all.
Buyers may think its overvalued and sellers think it's undervalued. They meet in the middle just the way they are supposed to if they want to transact now. otherwise they bide their time and take their chances. Both sides.
Yes, it's up to the parties at each end of the exchange transaction to either accept or reject the market maker's price. However, this approach produces unrealistic expectations about the future of bitcoin. In addition, it offers nothing of value to the bitcoin network itself, as all trading activity occurs outside the bitcoin block chain, which means that there are no transaction fees to compensate miners for maintaining and protecting (from potential attacks by rogue nodes) the bitcoin network.