I certainly feel it's about time I revaluated my witness votes, It's certainly helpful if witnesses have a post linked to their witness (usually seen as the chain icon next to witness names on the witness lists) that details what they are actually offering. makes it a bit easier at a glance to get a feel for the person.
Most tend to just link to their blog page so it's not really all that helpful as it's so time consuming to read recent posts and get a feel for what they offer.
Yes, we all should do that frequently. If you feel you are not getting what you want there is no need to vote on that witness.