There are several items currently in the game that are powerful in the laning phase that don't have a build path which encourages players to utilize them late game. In additon there are several situational/reactive items that are underwhelming outside of thier active abilities. As a result players feel punished for building these items when the slot could be used for something more powerful. This encourages selling back items after the laning phase or putting off building reactive items until very late. The items in my opinion most guilty of this are the following:

Haunting Guise
Soul Shroud
Spirit Visage
Brutilizer
Executioners Calling
Quick Silver Sash

I personally would love to see additional build paths for each of these items that would result in a final item on par with the likes of Infinity Edge, Black Cleaver, Phantom Dancer, Deathcap, etc. A great model for these changes would be the implimentation of Maw of Malmortius. Until its implimentatin Hexdrinker was an item that performed great early but offered little late. Now players have an option to upgrade to an item thats deserving of a late game slot.

Some suggestions I would have would be to combine Spirit visage and QSS with a Giants belt to form a final item. This would provide a solid magic resist item to tanks outside of Force of Nature. Combining Executioners calling with Brutilizer and a pickaxe could offer an alternative to Bloodthirster in most builds.

While my ideas are from from perfect I think the overall point remains: These early game items could use an additional upgrade path to offer players an alternative to selling them back or feeling underpowered late.

Soul Shroud is a complete item, it's just underwhelming. QSS is meant to fulfill one purpose, and any build path on it wouldn't be worth it.

Exec. Calling does deserves an item to build upon on my opinion

Culling blade:

builds from Exec. Calling and pickaxe.
STATS
AD:35
Crit:15%
lifesteal: 20%

UNIQUE PASSIVE: deals 8 damage per second over 8 seconds. can stack two times

UNIQUE ACTIVE: Inflicts target enemy champion with Grievous Wound, causing 50% reduced healing and regeneration for 8 seconds (20 second cooldown).

Spirit Visage and Brutalizer DO indeed need additional paths. I like Maw of Malmortius because it builds from Hexdrinker (underrated in my opinion). I would also consider Haunting Guise to be in need of one. Possibilities with Brutalizer are lifesteal, attack speed (without having to activate it) even some more HP + Armour Penetration (Similar to Frozen Mallet). Spirit Visage's upgrade could give you lifesteal, spellvamp or hp-regeneration. As for Haunting Guise, it could easily penetrate more Magic Resistance, give you more health, give you your own magic resistance or be similar to Odyn's Veil in the damage absorption. Riot's slacking in the item building area in favour of champion production.

Brutalizer does need some kind of upgrade path beside Ghostblade. Something to just give it a bit more armor pen and damage, but same cooldown. Something for the AD burst champions and bruisers.

I think I'd prefer half of these to just be made stronger in their own right. Increased in price to about 2k gold and then increase their stats to match the new cost.

In other words, make them items you buy in the mid-game that you don't feel like you're wasting the slot on come late-game.

You picked two of the four item choices that would most likely be broken with any additional paths. You chose the two that are most likely to be broken actually, but Haunting Guise and QSS are such that I had to throw them into that group.

As far as either item is concerned, XCode's suggestion was the most solid and the least likely to cause many problems, but it would require some changes to Ghostblade to rebalance it as a larger item.

The Brutalizer is balanced under the idea that you will upgrade it to Ghostblade (which is inefficient if you cannot fully utilize the active) or that you have to sell it later or be gimped, but the size can be increased somewhat to a larger item without causing problems, provided the total cost and value still remains below 2000, preferably no more than 1600. Ad+cdr is not a balanced stat combination on late-game items, and I don't want to get in another frustrating discussion about this.