Any thoughts?

Most mobs are weak against slash and crush damage, so blades may be better for leveling and I think there are more blade drops instead of piercing weapon drops but note that blades need 100% str. piercing weapoins 50% str. 50% dex so your weaponskill might be higher with piercing weps.

Same goes for your main rvr opponents, blades are better in my opinion, but in rvr blades are just an option when you ´ve enough realmrank to effort aug. Str. I guess. But there might be different opinions about it.

For leveling I would not think so much about your type of weapons but having a good envenom skill and enough switch weapons to bring dot on your target.

Leveling a nightshade solo is a pain, even more without good gear, so you might really want the best dot poisons on your weapons you can use with your level, also note that you can ´t use lvl. 40 dot for example when you ´re just lvl. 38 even if your envenom skill might be 40 with items .

For pve (and rvr) I would go with piercing.
Because of the evade stun and the dmg calc. 50% Dext/Str > 100% Str

You missed crush dmg with staves. It's a real option in pve if you want to spec full envenom/critical strike and it's 100% dext, so with crap items you'll have to focus on less stats (const dext quick hp physical resist) at least to the lvl 40.