Creating a whole other attack vector. An attacker waits for a huge pool to develop at xyz price and then comes in and buys it all at once, gaining cheap control over that amount and leaving everyone else with their pants down without moving price. In an organic situation, with the liquidity that naturally corresponds to the given case, price would rise in positive correlation, making each new coin bought proportionately more expensive and leaving market participants more fairly compensated on both sides of the trade.

Be careful with this can of worms being opened on HIVE!