Hmmm. Perhaps they'll adjust H2H so that it acts like a single handed weapon. Allowing stuff like Aftermath to operate on all hits of the main hand. This would breath new life into the RME weapons. Could also prove to be broken if they accidentally let AMs operate on ALL hits. Or they might do that intentionally to make H2H a White-DMG job by design.
Forgive me, I just like to dream and ramble on
I highly suspect that the current FFXI dev team can only add extra stuff to the old system or slightly modify the variables a little. They do not have the resources or ability to make fundamental changes to the system. Especially on stuff like H2H being treated as a 2H or 1H weapon.
Given what we've seen of their coding thus far, I strongly doubt that their weapons system is very complex at all for any weapon.
Their h2h system is probably an exact copy of DW except that the Main weapon clones to the Sub and therefore locks the sub weapon out. Which is most likely why things like AM effect are main hand, first hit only. Bad coding.
Our .Lua files are likely far more complex than the H2H parameter.
I'm not saying that they'll take the time to fix it but let's not get carried away and trick ourselves into thinking that it'd be hard to fix. Probably 3-4 hours reworking the code construct, an 8 hour day working on balance to keep it from getting OP.