I checked Whirlin's Bard guide, as I remembered some DS calculations there that were broken down by build.
https://gswiki.play.net/Guides_by_Wh...pon_Bard_Guide
Polearm seems to have worse DS than TWC, though I'm not sure if this is taking into account whatever bonus a main gauche in the off-hand has.
I think I'm going to stick it out with the TWC OHB for now, as it fits my character fairly well. If it becomes really dire later on, I can burn my free FIXSKILLS to go OHB/shield.
I still have to decide whether to focus on Air lore or Telepathy lore, though, and whether to try to fit in some MMC ranks at some point. I admit I'd never considered using Song of Unravelling.
As to Climbing/Swimming - I know 10 ranks or so of each are usually suggested, though I can't think of any hunting grounds I usually frequent under L30 where a Climb/Swim check is required. I was considering picking up ranks on an as-needed basis.