First - you're idea is unclear. You should label the top idea as a new item direction for Herald and come up with an item name for the bottom item idea.
At the very least you should list Herald's current stats somewhere in that post for comparison, because it looks very much like you done goffed on the stats/cost/builds with a current Herald vs. a new item.
Second - I'm not sure Herald's problem isn't the build order, overall cost, or slot efficiency.
I'd go more with the combination of stats it offers.
It offers way to little AD for a glass-cannon to consider, it offers way to little HP for a tanky derp to really feel good about, and it offers almost nothing to a support (especially now Riot forced AP ratios onto their utility).
Third - 1000 gold for a meager 200 HP and 10% CDR offers no incentive to upgrade Herald at all, especially seeing as you're spending the 150 combine-cost for nothing (as the 850 Kindlegem in that recipe offers 200 HP and 10% CDR).
The average game sees 11,000 gold per player, which breaks down to about 1k in boots, three 3k major items, and 1k in the bank when the game's over. Slot efficiency is not something with a price tag in LoL because of that.
Also on this - the more expensive items get in LoL, the more cost-effective they tend to become, pushing players to work on 1 item at a time until it's complete (rather than filling it with a bunch of cheap items then working up).
Fourth - if you're going to come up with a new item upgrade, give it a name, unique, and unique name that all point towards a very specific niche and champion build they fit into.
Herald seems like it's got potential for a fighter lacking in team-fight potential to bring something more to late-game fights, when they're at a slight disadvantage, road out their power spike, and otherwise are having trouble forcing 1v1 strategies.
If it's going to be enticing for supports, making the item not suck on supports could be nifty - as well as offering aura stats that feel good on more than just a marksman.