Changing the subject, I've done my calculations again. Found some mistakes I have previously made (e.g.: I was calculating VM Rod and Staff's eMATK with the same formula as Crimson Rod, but in fact they lack the "+5 MATK per 10 levels after 70" part - they have it bult in their wMATK).
So, basically
* +14 SoD is better than +15 general use Crimson Rod (Neo Punk + N. Mimic) and +15 Specialized La'cryma (2x racist cards), but starts losing to all of them as soon as 100 MDEF.
* A +14 Sunflower Boy with 2 racist cards (who would slot them in?) is the BiS until 135 MDEF, unless you consider a "perfectly charmed" VM Rod. After that it loses to all others. To be more precise, it's 13% better than a +14 SoD with a single racist card.
+ These MDEF numbers are considering a +9 OBMH. The threshold will surely go higher with the OMBH upgrade, but all of them will lose to a VM Rod unless you have a +20 OBMH.
* At +13, ignoring charms, VM Rod starts being better than both aforementioned rods (~2% better).
* VM Staff was a huge letdown. It's less than 1% better than the VM Rod ignoring the charms, because you're locked on using OBMH, and since you need the second charm to be "Bypass X% MDEF from Y race" for consistency, you're pretty much throwing one charm away. Also, it's only 2.8% better than the Generic Crimson Rod and 3% better than the Specialized La'Cryma Stick + Pororoca. If you have an usable "+X% damage against Y Property Monster" on the first charm it will be better than these rods by this amount, but the VM Rod is still better. Also, you won't need to drop your shield.
* OBMH is still the best headgear when using Crimson Rock and Earth Strain by a very nice margin (Jack Frost as well, but you know... :v).
The comparisons were made between the average effective MATK produced by each setup when Recognized Spell is active. Other gears were unslotted Sunnies + Mob Scarf, +12 RWC Pin for Rods and +9 OBMH for Staves, +11 Flattery Robe INT2/2, +9 Temporal Int[N. Verit] (+7 Pororoca Shoes for La'cryma), +12 FAW [Spell 19][NAM or Antique Book], +9 MBS[1] (with bypass card for Crimson Rod), Psychic Magician's Glove, Psychic RWC Pendant [MATK+6%] or Alchemy Gloves[Scaraba], +9 Magical Shadow Set.
Conclusions:
1) Best Weapon is a specialized VM Rod at +13 or higher. I didn't test it, but I'm pretty sure it's already better than all other weapons at +12 with decent charms (~10% bonus on race and element, even a bit less than this).
2) Best for lower cost weapon setup is a +15 Tomb Raider's Crimson Rod of Echo. You might also want a +15 La'cryma stick for those races that you don't have a specific MDEF Bypass card combo.
3) Now you can play with staves, but they are still unefficient.
4) Since all numbers were calculated for Warlocks, with Recognized Spell active, these results may differ on Sorcerers.