Mod 9 likely won't change the current problem of random weapon drops not giving the possibility of anything with respect to dps compared to existing greensteel. Example: what's the ml on a +5 holyburst of pure good? Unless this item also happens to be silver (rare drop indeed), it isn't even as good as your typical double positive let alone triple positive on Harry.
So what are some ways we could make ML 20 loot potentially more exciting?
1. Add the elemental blast prefix to the general loot list (ML ???).
2. Add a better bane. Like superior bane or fierce bane or whatever. Or as has been suggested make existing bane effects bypass dr of the appropriate monster type. Assuming they did that, what would be the best plus you could get on a holy burst of greater bane weapon and still be ML 20 or less? Would this weapon even be as good as a mineral II on Harry?
3. +6 (or even +7) attack/damage modifiers for ML20 weapons? If there were a small chance at a better modifier, this would be exciting. I don't think it should be commonplace though. Could also have a higher plus pop up on a few named or raid items. (Might also want to make these modifiers possible on armor/shields, especially if ac +10 bracers are possible at level 20.)
4. Re-balance base damage on all weapons and make greensteel the same base damage as all others. I don't like the idea of any major nerfs to greensteel to balance it, but I think this is a nerf we could live with. I like that the devs previously took a second look at some weapons (like the great xbow) and changed the base damages. Its time for a third look. Go back and revisit each weapon. What's reasonable for a bastard sword? 1d12? 2d8? Decide and make it so for all bastard swords, including greensteel.
5. 3rd prefix/suffix for quarterstaffs. Monk? Acrobat? Casters? I know there are people using these, but I just can't seem to find a place for them on any of my characters. I was thinking that these weapons could use an additional attribute, perhaps as some sort of general favour reward (available to everyone) or as a class enhancement. Example: your wizard either achieves a a certain house J favour or purchases the class enhancement. Now he/she can do some sort of crafting which he gets to choose from a list of attributes (eg. fire lore, spell penetration, etc..) to add a third attribute to an existing quarterstaff (named, raid, and greensteel excluded). So now with respect to spell-casting the convenience of a 3 attribute quarterstaff has to be seriously weighed against the much more common 4 attribute (total) dual wielding scenario.
For monks/acrobats, the possibility of adding a 3rd enhancement of the damage/effect type to regular quarterstaffs to beef them up a bit would be nice, but I don't think overpowering.
Other suggestions?