I thought the full iambic pentameter was only for a skill tree? Doing it for all of a companion's dialogue would be... rather impressive, and also possibly insane.
I believe he said the skill tree was a dare. The speculation about Solas started with this tweet:
Half of what Solas says is in a rhythm that only his VO and Patrick Weekes know. #PAX
And then sort of put that together with this tweet (among others) from a while ago:
Patrick Weekes @PatrickWeekes
When you leave stuff on coworker while you go on vacation and have to specify that in case it comes up, this bit is in iambic pentameter.
And then speculation happened.
And I admit I was the one who got all symbolic on everyone and waxed eloquent about Shakespeare and what it means when characters speak in iambic, the difference between that, prose and rhyme, etc., etc., and it ended up fitting so well with our current perception of the character that it became a popular idea. (that video of Kenneth Branagh speaking it certainly helped)