The textarea approach is the dangerous one that would need to be validated or the page can be broken easily.
The safer approach of allowing key value pairs for meta or links requires more development effort. Ideally we would store those key value pairs in a related table for easy user management of them but then pre-compile the markup into a single field on the mp_Pages table so we don't have to make extra db hits to render the page. This is my plan, I actually already have the field on the mp_Pages table but have not yet built the related table(s) for managing the meta data. Actually it would be more than key value pairs since there is also scheme.
Best,
Joe