Suggestion: Use healing items on others
There are many times I've taken the infinite ammo amp and stocked up on nothing but health items (when I don't feel like spamming the map with grenades) but making good use of this combo has been tricky. While retreating and finding a defensive spot it works fine, you just drop what you need and your team heals. However, if in a really tight spot you end up working overtime trying to make it work.
Granted, it's part of the gameplay, but for this particular amp it could be made more useful than simply being a poster child for spray-and-pray. By allowing healing items to be used on a different player it could make gameplay more synergetic and introduce a rather strong feature. The player being healed and the player doing the healing both have to stay put, like now, with the healing one using the item but the healed one allowed to watch and shoot, and use abilities that don't require movement (Bloodhound's tactical, Sparrow's tactical and ultimate, Conduit's tactical and ultimate, etc).
I'm not sure how this would play out, it could potentially become rather overpowered (especially end-game) where others than Lifeline could provide such healing (except she's free to move about). It could be worth trying out, it could be fun, but it could also upset the current gameplay quite a bit.
EDIT: Considering how other amps work it wouldn't be a very good change, all other amps would need to be changed in a similar manner providing both an individual and a team benefit. It was just a spotaneous idea, which with a bit of thinking isn't quite so good and rather unbalanced.
Heal Overflow and Bottomless Batteries would also work really well with this system, providing a very useful team benefit, but Over Armour and Power Booster would fail here unless you could donate shield and use your tactical to reduce someone else's cooldown. Reducing tactical and ultimate by donating your own could be incredibly powerful, probably too powerful, but could work here. Over Armour would be weaker compared to the others, one bar isn't that much, but would allow players to donate shields and top up an important player.
Considering controller players there might not even be enough buttons to make it work with current schemes, but it would be a rather interesting gameplay, pumping whatever tactical or ultimate you have into Loba to help the team rearm after a respawn, to get Wattson's Pylon going, Ashe's ultimate for escape, or a whole bunch of tactical's that would quite literally become even more tactical.
However, balance is the key and might be tough to pull off, not to mention the controls for it.