I don't think increasing Rageblade's cost by 300 is going to do much
It will only slightly delay the abuse champions from reaching their massive powerspike with the item. Right now it gives 5k gold worth of stats without its passive and with its passive it goes up to nearly 6k. For an item that costs less than 3k gold. That's over 200% gold efficiency. Riot either needs to make it harder to ramp up the stacks or nerf the stats and/or the passive.