I used to absolutely love 8-9 multi-boxing a full party of characters. I always used to multi-box on Lineage 2 back in 2004-2006, and in the latest Lineage 2 Classic release as well. Everytime I've re-engaged in multi-boxing, I have to of course get accustomed to it again along with the demand for multi-tasking. Over the days and weeks it takes to get a good rhythm going, it can be quite an adventurous and thrilling experience to find all of the different builds, skill combinations, and attack sequences that you can muster with particular help of the ever-generous and original in-game macros of Lineage 2. Multi-boxing definitely came with a lot of conveniences though, where I found myself no longer reliant on group play and able to even put out heightened DPS at Raid Bosses. Although, aside from the occasional friend or two enjoying the group party buffs, I found that it was a very isolating playstyle. In addition, there was a divide between myself and many other players out there in the game world who simply don't benefit from this style of play and at times over-populated certain grind spots where others could have joined in instead. I've had a range of experiences, from good to bad.
Ultimately, I found that the essence of multi-boxing was to provide yourself with a convenient advantage in some way/shape/form in a bit of an unnatural way. Sure, it may be original to Lineage 2 and can be challenging and interesting for a while (especially for adding an extra dimension of actions inbetween the over-relaxed parts of the game), but at the end of the day counterproductive to most healthy experiences. It can be self-defeating towards the overall enjoyment of the game for yourself and others. In addition, not everyone has the hardware capability, or the time and energy to invest to such extent. Time-to-win and Pay-to-win can be very similar concepts to this at the end of the day. I could go further into details, although I don't want to go too off-topic into game design and philosophy.
I'm sure others have general concerns in regards to exploiting the ability to connect with so many clients for the purposes of botting or using automated programs as well.
Regards
// Edit:
I hope that this general feedback is helpful for the Lineage II Design and Development team, as others have pointed out the potential divide that it causes between players and their in-game experiences. @Sunshine