Question regarding RDM stats and weapon choice.

[Vorx]

The actual main stat for an RDM is Intelligence. Unlike a melee RDM weapons attacks are infused with magic, higher your magic better your damage. Its also a good idea to add Strength Materia for your auto hit in between the casting. It won't be much but an extra 2-300 hit will add up.
RDMs naturally crid hit so you don't need to really worry about that, i've only not crid hit maybe once or twice a week.

[Elleia]

Spell speed isn’t very worth it for RDM because half of their total casts are instant - and spell speed does nothing to buff those instant casts. It can also make it difficult to double weave oGCDs. RDMs will get much more mileage out of crit, direct hit and det because these stats apply to all of their spells.

Also, melding strength is not enough of a DPS increase to be worth it.

[HaroldSaxon]

Spell speed isn’t very worth it for RDM because half of their total casts are instant - and spell speed does nothing to buff those instant casts.

That is incorrect - it reduces the GCD even for dualcast spells

It can also make it difficult to double weave oGCDs. RDMs will get much more mileage out of crit, direct hit and det because these stats apply to all of their spells.

Also, melding strength is not enough of a DPS increase to be worth it.

This is true, although mainly you avoid spellspeed because it doesn't affect OGCD damage or your Melee combo.