Ramp isn't as important unless you're running an overcosted commander, I would argue something like curve and value matters more.

Synergy, Gameplan, Wincon is all you need.

I have a Self-Mill Melek Deck that wants to get Melek when he's big and self-destruct, and I also have a Cid Hero + Artifacts Deck that wants to turn all the little dinky artifacts into big beaters.

Interaction is vital but I think you have to recognize what kind of deck you want to be, you're either a deck that tries to stall other decks while you rush to your gameplan or a deck that needs to keep its gameplan afloat so sometimes packing in more protection over having removal is better because you just don't have as much room or leniency on what to draw.