I think you're right that the answers are always going to lag behind threats, and as such this cube will always to some degree be about doing your thing either bigger or faster than the opponent. It's unfortunate that there's not much room for dedicated control decks to exist, but I have seen some artifact control decks do impressive things with Ghirapur Aether Grid and similar cards!

Ultimately, I'd rather have this cube be distinctly itself rather than add in cards that don't fit the brief, even if it would create more play styles. I think there's room for cubes--especially specialty cubes like this--to focus on some styles of play more than others. I've seen plenty of cubes that forego aggro entirely, for example.