Xypherous recently posted an article on the PBE site about planned item changes in the 4.3 patch, primarily affecting supports. None of these changes are on live at the moment, and the article mentions that additional changes will likely be implemented, but this article provides an analysis of the changes and the impact that they could have on the game.

Boots change:

Cooldown boots will now be tied with mobility boots for cheapest boots 2 in the game. It's a slight nerf to the 'CDR Thresh' build, and that's pretty much the only major impact I see it having. Mobility boots are now even better on supports than they were before, due to their decreased gold cost, and 200 gold at the point in the game when you want to buy boots 2 means a TON on supports. However, they're massively nerfed on junglers, who really need to have as much MS as possible when ganking, especially in toplane.

I think we'll see many fewer pickups of Mobility boots on junglers (not that we were seeing it as is), and more on supports, as there will be a lot of times when a support simply needs extra movespeed ASAP and so will want to go for the cheapest option.

That said, the changes to mobility boots somewhat make sense for what mobis "should" do.

A quick look at the CDR values vs cost: How much is CDR worth? We can define from Kindlegem or from Fiendish Codex. Kindlegem definition has 5% CDR worth 161 gold; Codex definition has 5% worth 83.75. In either case, cooldown boots are becoming more gold efficient.



Coin Line:

Let's look at some of the numbers. For Ancient Coin, you were getting 3 HP/5 and are now instead getting 5 HP when a minion you don't lasthit dies. If you never kill a minion, you will be getting 6*5=30 HP each wave (not counting cannon creeps), or 30 HP/30, or 5 HP/5. This is a significant buff to the amount of sustain you will get.

How much is this regen worth? Rejuvenation Bead gives the exact same amount of regen, costing 180 gold. This is a 72-gold-worth increase over the current iteration (you gained an additional 2 HP/5, so 2/5 the value of a rejuv bead), assuming you take no last-hits.

Note that this is a slight nerf to roaming supports buying Coin because you aren't present for the last-hits.

The loss of 1 MP/5 from Nomad's Medallion is a 60 gold decrease in its worth (1/3 the value of a Faerie Charm), so in terms of gold efficiency, the medallion only has a very, very slight buff from this change.

Overall, Coin's power is staying fairly close to the same, while the other two paths are being buffed. This makes sense due to Coin's overwhelming popularity at the moment.

Spellthief Line:

Let's talk about Edge/Frostfang first. It's very difficult to quantify this change or even determine whether it's a nerf or a buff. If you have complete control of the lane and can harass either opponent at will, the item is weaker, as you're only getting one charge per ten seconds (on average) as opposed to two (two enemies in the lane). On the other hand, if you're rarely able to harass the AD carry and only sometimes able to harass the support, you're getting additional GP10. The change from AP to extra damage is a nerf on sustain-based champions who scale with AP (Soraka, perhaps Sona) but a buff on champions with somewhat lower AP ratios who want to harass with autoattacks (Lulu, perhaps Annie depending on matchup---Annie/Caitlyn will see this as a buff).

The change to Frost Queen's Claim, on the other hand, is a massive buff to the item. It retains its 2000 gold price tag, loses 10 AP, and gains 10% CDR. The 10% CDR is worth approximately the same as the 10 AP from a gold standpoint (refer to above CDR worth table), but the slot worth of the CDR is enormous. At the moment, getting no CDR from your gold-generation item is extremely difficult for supports to deal with, even if it's an AP-oriented champion who can pick up a Morellonomicon, but with this change you can buy cooldown boots, Claim, and one 20%-CDR item and be maxed out.

Of course the most noticeable change is to the active effect. A cast range of 850 is important because that outranges most gapclosers, and the fact that it's ground-targeted instead of enemy-targeted means that it's now significantly easier to use when running away; the increased slow magnitude means a lot as well. At level 18, the total damage will be 230, which is enough that champions with low MR like ADCs who you're chasing down or supports you're catching out will actually notice a decrease in their health bar from the damage that you deal, even if it's still slight. For reference on the AoE size reduction, the radius of the slow field from an Iceborn Gauntlet proc from a ranged champion is 210.

Targon's Line:

Relic Shield---You lose 6 HP/5 and gain 40 HP upon a last-hit, so you gain 40 HP/60, meaning that the very early sustain to yourself is almost halved, but given that you're giving a lot more sustain to your ADC than previously (2000 HP is the break-even point between live and the new flat value), overall the two of you will have more sustain assuming you're able to use all your charges.

Targon's Brace---Here you're only losing 4 HP/5 and giving yourself 50 HP/30, so you now have more than double the sustain you get on live from a Targon's. However, again remember that this sustain is only granted when you're using charges, so it's a nerf to roaming with a gold income item, though a smaller nerf than that of the Coin path because you can still get 100% efficiency even if out of lane for almost 90 seconds.

Face of the Mountain---This item is now clearly intended to be used to shield your ADC. It will be almost worthless on yourself or an APC or a tank; it's intended to be used to save your ADC. To look at a comparison, you would shield your ADC for 200 at 2000 HP or 300 at 3000 HP. With BT LW, your ADC will have 140 bonus AD; with IE BT LW he'll have 210; after adding in base AD and multiplying by 1.5, you'll have bigger shields at most points in the game. The removal of the health cost also means that you can easily shield your ADC at the beginning of a fight without too much cost to yourself, and the scaling off target's stats rather than your own makes it more viable on ranged champions. That said, the lack of mana regeneration still makes Targon's an awkward pickup on poke/trading supports.

Ruby Crystal:

Despite what the patch notes say, I completely expect Ruby Crystal to become the standard starting item on a lot of supports. The 400-gold cost makes it only slightly more expensive than the GP10 options, and you would almost certainly be able to buy a sightstone on the first recall, needing only 450 gold before recalling. The earlier sightstone lets you buy an earlier sweeping lens, which will actually force your opponent to buy wards for constant vision control as opposed to relying on trinkets.

The health-gold efficiency was almost completely unaffected.

Doran's Shield:

This change was long coming, with Doran's Shield being the standard start on nearly every single toplaner and every single support. This nerf combined with the buffs to the three GP10 items and to Ruby Crystal as a starting item lead to the result that I believe Doran's Shield will almost never be purchased unless it's against a lane like Caitlyn/Lulu that is extremely reliant on long-term autoattack harass, and the item is being bought primarily for the Block passive.

In summary, these changes should have their intended effect of leading to significant item diversity among supports. Talisman will still probably be the most standard pickup due to its massive versatility, but Frost Queen's Claim now has significant appeal, and Face of the Mountain can be purchased effectively on a wider range of champions. Doran's Shield may still be picked up, but likely not as a first item on most supports, and Ruby Crystal will be an extremely viable starting option.