The poison proc from Dragonspine Rapier lands on Statue fwiw

Cool. If they ever fix rogue slow poison to 95% snare instead of root, that might actually be good to get it 50% slowed at the start of the fight. It probably breaks root too often though with it doing root instead though.

Do weapons proc at different rates? Could that be a factor to consider?

Also, is the difference in DPS strictly the % difference in dmg/delay ratio?

Not at this point in the game.
The ratio on the Tuna is notably better as is the root proc DD vs Strike of the Chosen (about half the DD but a tap). As if it it really matters? Meh. Most parses are subject to scatter due to duration. If we had 30 min fights it would be easier to notice in practice.

Anyone with a Vulaxe can get a Tuna sword. The opposite can’t always be said.

Unresistable spells are surprisingly effective here.

Also worth noting that root proc is an aggro effect, same aggro as a stun or slow proc, even if the mob is immune. And the dd portion adds aggro on that. So the Tuna sword's proc is for example a bit more aggro than the Dain axe proc.

Do a lot of mobs resist the proc from the Tunare sword? I've heard that, but is it resisted anymore than a standard paladin root would be?

And does weapon AC count as shield AC?

some weapons yes, in this case both tuna and vulak do

i dont have issues with resists unless the mob is flagged for it