Alrighty! MT is now running against MySQL, which I was hoping would improve rebuild performance.
Could I even do brute pforce category reassingments? Well, maybe; but sadly the fields under “entry_category” are … null. So; hm, still pluggin’. I guess I’ll have to, like, RTFM and find the schema.
Always always the tradeoff b/t the convenience of access and speed, especially in large-scale operations, in server-oriented apps. Always.