Getting additional value for spending the mana to cast big stuff will mitigate some of the disadvantage of investing so much mana into a single thing
Id mostly consider it an equipment commander, as its a poor choice for a straightforward goblin theme
In a well-built, low-to-the-ground deck, Dark Confidant is effectively a Phyrexian Arena that swings for two--with a low curve and 35-40% of your deck being lands, you'll average out to taking one damage per card
Whether dungeon crawling cards or the D&D classes that get transposed for Magic gameplay, there are plenty of anchoring elements for D&D players to find comfort in and finally fall in love with Magic and vice versa
Some despise it, claiming it's a prime contender for the MTG banlist
And dont worry about any defensive measures your opponents take, since thats what Flusterstorms here for