It's rather a bug report than a suggestion, and also wanted to make a video about it for any1 who don't believe it but got totally no time atm so will just write it down.
Kinda long ago (guess approx since juraid deva last hit determining the winner was changed to more dealt dmg [i know it was reverted back to last hit already long ago too], drain in pve was changed aswell and now it doesn't count (or only like 15-20% of the drain's dmg counts max) as dmg input for taking the loot. Which i have no idea why had to be changed, since it was smth working the same way ever since KO was released, furthermore Sin's dps is hella sux w/o the drains as most of their skills is not failsafe, as well as no additional dmg (spike, thrust, etc) ---> hello 50 spike dmgs on felankor etc. Pretty sure many ppl didn't even notice it was changed but feel free to test it yourself.
-Normally drains counted as much as physical dmgs (A boss having 1m HP --> you drain it with 10% drain --> it counted as 100.000 actual dmg) and helped tremendously for the sin's party to take the loot of the boss.
-But few months ago it was changed and atm if you drain the very same 1m HP mob, even tho it still dmg it 100.000, but as far as the fight for the loot goes, it will only worth ~0----> 20.000 dmg max.
In the past (since the ancient KO times) if 3-4 Sin teamed up and timed their drain fine, they could steal bigger mob's drops. But now drain dmgs hardly counts in the fight for the drop, making sins almost irrevelent in most important PVE fights. Causing them to mostly lose etharoth / atros / other not 1-2 hit boss's drops against other classes as well as making boss (felankor, ultima, etc) fights less thrilling, since w/o drains making a diff, smaller parties have no chance of getting the drop, only the 8men fll warrior , archer , other parties taking every drop as it can be seen everyday.
PS.: I could somewhat understand reducing drain's effect in loot fights for big bosses (Felankor, ultima) to avoid fll side sin drain ks parties (still wouldn't agree with it but could somehow live with it. But even then, not reducing it to such extent as it is currently, which is almost useless).
But they should calculate with 100%'s of drain's dmg against smaller mobs like etharoth etc for sure.
Sry for the typos, wrote it from phone.