Ok, so, you take swords for nice weapon selection, giant strength for nice parry, and you get passive damage from riposte. Also, you end up with far more damage overall than polearm which is a huge bonus in most situations. Sure, polearms are harder to defend against but dual wield makes up for it in most situations. Also, legsweep is far more reliable than trip but suffers the same limitations and you're usually better off doing a different skill.
As for landslide, if you can't trip someone because they're flying, and they're affected by some sort of protective shield or 2 sizes smaller, so no bashing, then you can use landslide as a giant reliably well for lag because drive seems to have a size component.
Also, you can use mostly offensive wands, etc. Having said that, it's possible that word of recall is "offensive" since a person must be "trusting" for it to work and Yes, you can drink/quaff potions in combat.