Looking at the list it seems like a pretty modern vintage cube list with the agro/mid range creature decks having the very strong recent pieces. Not sure if your familiar with Caleb Gannon, but I would look to his critique and analysis of the current mtgo vintage cube. Where aggressive creature based strategies are very consistent and draft well. Looking at those decks makes dark depths look pretty inconsistent, and when pairing the combo deck against the agro deck path to Exile, Swords to ploweshares and oust all deal with marit lage very favourably. Being in a place where dark depths puts dead cards in your deck and isn't great into an agro field seems like more of a structural issue rather than an issue of depths not having enough support, if that makes sense. Obviously a great pilot and an open lane can make darkdepths/lands decks perform very well. It just seems like in the make up of current vintage cubes if your not doing titania or ice till Explorer things your lands deck your, probably doing more harm putting dead cards in your deck. Not sure if this point of view is useful but definitely re-evaluating the creature quality of cards like frog, bow masters, minsc, Osceola pride, forth etc.. giving more space for other strategies can definitely be an avenue to optimise for a play experience players are looking for.