First, this 5-color commander gives you access to all the monarch cards
The main issue with Raubhan is getting to the attack stage since it doesnt have Haste
Perhaps an Anthem of Champions of your own
Following the same principle, you can adjust your land count based on the number of cost-effective mana-producing creatures in your deck like Llanowar Elves, or cards that help you retrieve lands like Many Partings, which essentially functions as having an extra land in hand
Being a non-rotating format, it is constantly growing as Magic releases more and more sets, but also means that it is relatively stable, at least when compared to Standard
Whenever a creature deals combat damage to you, remove a point counter from this artifact