It isnt hard to reach seven mana in Magic, particularly in control and ramp decks, so getting it out ahead of the curve is going to be a common occurrence
It is, in effect, a chaos draft in a pack
Hand knowledge is a pretty powerful thing in Yu-Gi-Oh, hence the ban
(If they're equipped to the same creature, the abilities of the equipped creature will also trigger three times.) An ability of the equipped creature that triggers when a card is put into a graveyard "from anywhere" triggers twice only if (a) a creature card was put into a graveyard from the battlefield and (b) The Masamune is still on the battlefield and attached to the creature with the relevant ability
The Doctor has faced off against several powerful enemies in their past, each one planning to be the one that finally defeats the Time Lord
Could open the door to some cool stuff, could be that asking to both have out a bunch of creatures and also a bunch of equipment spread around on them rather than just cramming a dozen swords into your Commander's hands