I'm thinking that the best resource for me, personally would be

the ability to save a grouping of cards, and auto-rent the lowest DEC for the BCX you want

So you could make like: "Water Daily Team" and you'd rent that, and it'd auto-add those to your cart for a quick way to rent for dailies

then you could have other templates like
Neutral Core
Splinter Dailies Teams
etc. etc.

you'd still probably need to manually rent for Gold Foils, but for me, I often rent my ideal team as non-goldfoils, and then upgrade them to goldfoils as I need the power.