Absolutely agree. BIfrost does have the potential to function in this capacity, but will depend on the other agendas in the deck having abilities which fall into this category.
If HB got a card like Philotic Entanglement which keys off number of agendas scored/stolen then that could provide a strong enough motivation to run multiple small agendas. That does tax the runner more as well, since the payoff for a single run is lower, but the costs to do so remain the same.