Catch all Lookup tables are the bane of my life.

I've lost count of how many times I've had to write queries which join to the same lookup table 10 or more times to retrieve some basic data items.

As your article points out, it makes enforcing business logic very difficult, sometimes these data values can be mandatory but there is no straight forward way of enforcing that.

It also hides the true data structure so when someone new to the database is trying to mine the information schema tables to try and find certain data items they find themselves unable to locate key columns which have been instead hidden into a lookup!

Finally, the performance hit. All the extra processing which has to go on to flatten the data from the lookup tables. Storage is cheap, CPU cycles wastes energy!