Site's 9 years old and the marketing pages are the part that keeps breaking, plugin update, security patch, some builder conflict, and the homepage looks off til I go dig through it. The blog's fine, ranks well, I'm leaving it alone. Anyone split the marketing side off and keep the blog on WP, or was running two setups more hassle than it was worth?

I'm moving a site about 400 articles deep onto a clean CMS and the migration is the part scaring me. three writers over four years, so the fields are all over the place, inconsistent bios, a chunk of pillar pages orphaned. traffic's fine, it's just unmaintainable. What i'm stuck on is the actual move. how do you standardise the fields and get 400 old posts into a clean structure without hand entering every one, and without a rebuild quietly rewriting pages you didn't touch? i'm not a dev so a script isn't on the table.

How have people handled a migration this size?