look up Ashes of Creation, founder was old L2 player who left before GOD to other mmos, and now work on own modern mmo with like 60% of L2 mechanics/content and lot of new things to do from other popular mmos. Its not amazing yet, animations/UI/gameplay need more work, but their concepts are great.
About topic, i dont think any port of L2 to new engine would revive it for more than few weeks - people are just bored of what game has to offer, exactly same gameplay for 10 years is just no fun, so without major changes and constant updates, it will end just like any other regular priv.