Not sure where your math is coming from. I count 30 Regalia per weapon copy, 5 fragments per Regalia (limit 20 Regalia per month if you want to get the best price). That's one weapon copy per 1.5 months. The weapon has stats that are nearly as good as an MLB SR at LB1, so 3 months of farming to get a useful copy you'd actually want to equip, assuming you don't spawn any Ragnaroks or trade at higher prices. That's not ridiculous, assuming you're only farming for the Soul you plan to use most.
As for Charles Blast, that's the option of last resort. You really don't want to be maining D'art unless you have no other option to reach the debuff caps. Also, Charles Blast has an HP buff instead of the elemental attack buff. Do you really want to trade elemental attack for HP?