I would rather have the lore glossary personally. The 2014 monster rules work fine for me and I don't mind updated ones showing up in the MM (or not at all). I love making monsters, but I don't think making monsters is a requirement for a DM. However, I don't really know a lot of the D&D specific lore as I didn't really buy anything outside the core books for 1e, 2e and the BECMI books (until 4e). So my "canon lore" only consists of primarily what is in the 1e MM, MM2 and 1e Deities and Demigods really.