Captchas, even server-side, leave residual data behind from their code, and there are programs that read that data to crack the code (whether image or text, the data is there) for you. Putting them at random spots is still determined by x/y coordinates, which again, is present in the code for Captchas. This coming from someone who has suggested Captchas in the past; they do nothing.
There are a few games out there that have a combat system in place that basically does not have a targeting system, which actually prevents the average botter from functioning (they’re not without some bots, though). With the directional attacks, and AOEs in this game, they could do that here… But then, there’s other software out there around that (targeting the enemy based Monster ID, or using image recognition software scripted into commands, for example).
There aren’t many “basic” things they could do to prevent bots. Also, for those suggesting it, programs HackShield doesn’t exactly do a bit of good if ANY of the data can be modified client-side (including the client itself), or if, ya know, they can just modify the client data directly to bypass even detecting the program. Setting it up to detect whether or not a file has been modified, adding file and code encryption, and restructuring if anything has been modified might help for a while, though… However, botters outnumber those trying to prevent them, and they pretty much have teams set up to counter any patch or any method put in place.
The only way to prevent bots, at least, RMT Bots, is to remove their reason for botting. Right now, that reason is because of all of the restrictions in place against players, making the environment almost P2W. While yes, the 48 hour wait time between market transfers, and preventing transfer of Silver through any other method makes some sense, the immense tax (10% is typically max in any game, and you sure as hell don’t have to pay to get it discounted to that price), the requirement to have Tokens to raise your amount of trades (in market or otherwise), and having trades restricted in the first place… Tokens are only valuable to the average user BECAUSE they increase trade limits and increase market slots. The rest of the stuff is meh, and totally not worth the $18 USD worth of TP (staff has said 100 TP = approximately $9 USD) for 30 days that they seem to intend on charging us.