Here is a list of my item concepts, some may be useless and just niche at best, some may be outrageous.

Ancient Sash [Legendary tier]
- 3900g
- Quick Silver Sash + Needlessly Large Rod
- 45 MR + 80 AP
-Unique Active: Removes all debuffs from your champion, your champion gains 10% Spell Vamp and 35% crowd control reduction for 5 seconds (90 second cooldown)
--- REASONING: APs in general have been underappreciated lately due the changes and progression of the game, burst mages like Veigar, LeBlanc, Annie, etc. have Zhonya's hourglass to wait-out an engage then burst or instagib. DPS Mages like Swain, Cass, Ryze, etc. can do the same, but their damage-output curve is low to high as long as they continue to fight, so if they Zhonya's they may risk their team dying and/or may not be able to clean-up and get focused after Zhonya's active is over and not get a kill in due the nature of DPS mages.

The Warrior's Mug [Legendary tier]
- 2900g
- 35 MR + 45 AD
- Chalice of Harmony + Pickaxe
- Unique Passive - Mana Font: Increases your mana regeneration by 1% per 1% mana you are missing.
- Unique Passive - Based on the damage dealt to champions, you gain 5% of the damage dealt as mana.
--- REASONING: It bothers me that there isn't an AD version of Chalice yet. And yeah, this item is more specific to AD casters and allowing more counter play.

Cursed Impaler [Mythical Tier]
- 3500g
- Giant's Belt + Atma's Impaler
- 400 HP + 55 ARM + 20% CRIT CHANCE
- Unique Passive - Bold Force: You gain attack damage equal to 1.5% of your maximum health.
- Unique Passive - For each 5% percent of health missing, you gain 1% additional critical strike chance.
--- REASONING: Atma's has potentials to be a force to fear (especially in this defense meta), but only certain champions can utilize the most of it. People complain on how attack damage bonus is rather weak, I think it's powerful and I thought of an item that could definitely see use today. Also, game modes exist that don't have Warmogs (looks at Dominion).

These are just some I came up with. Whether you think they are overpowered or just useless won't matter to me as they're not part of the game.

you are right with the Ancient Sash for a long time i was thinking WHY THE HELL IS THERE NO AP ITEM LIKE THE ONE QSS AND Big F**king (or best friend) sword build in to (cant remember the name at the moment) they need to add this item so the mages have a way to escape in a tight situation when caught out of position

It'd be nice to see Atma's build into something a bit stronger since it's been a while since I've seen anyone build it.

Your Atmas item would have too strong of synergy with certain champions, especially Tryndamere, however it also sounds like an interesting option for some of the other melee carrys. Another problem is with all the health stacking we already see, I would hate to see a ranged ADC with Warmogs and your Cursed Impaler... and I wouldnt be surprised to see it.. It would have to somehow be made into a Melee only item and it encourages the already very strong health stacking meta.

Yes that was the purpose of the Atma's upgrade, AP Tryndamere is apparently more "viable" than the way he was meant to be played, same thing goes with Master Yi. Melee carries aren't an much as a "sub-optimal" pick, this item can still encourage these carries to go bruiser and still do respectable damage, if they start to fall behind. Atma's still isn't seen much these days (I have not seen it at all since the first pre-season patch) regardless of health stacking going about. It's also an option to those who seek crit. chance in their builds like Garens.

I don't think so, it only gives 20 more HP than "Gaint's belt" and it's rather costly as well. ADCs would have to buy warmogs as well as this item to purposely abuse it's passive damage and crit. chance. that's a total gold cost of 5130g which can be used to make other health shredding item combos like Statikk Shiv + BotRK (very effective on Kog 'Maw) especially right now on the PBE their making BotRK give attack speed.

Thanks for the replies so far guys!

Atma's a long long time ago actually used to be strong and gave 20% crit and 2% of Hp as damage. It was nerfed to its current state over the years because it was too strong. You can see its Patch History here:

http://leagueoflegends.wikia.com/wiki/Atma%27s_Impaler

I know, I played those times before. That's why I never buffed the damage bonus percentage. :P

But right now Atma's Impaler is being overlooked thanks to that nerf a long time ago. Getting 60 AD at 3k health, can't imagine if it didn't get nerfed now. But I still like this item and is very nice in crit/bruiser builds.

I think it would be better if Atma's got rid of the crit. It doen't really fit with the item. Its meant to be a bruiser or tank item but current Atma's doesn't give enough armor for tanks and not enough AD for bruisers and neither of them really need crit . It would brobably be better if it just gave a base AD of about 20 or 25 in addition to the unique passive or raised the armor bonus to about 70 because 45 is a little under wellming. Its only about half the armor of normal armor items.

Was hovering over downvote button. Read through it. Not sure about things now.

Will come back later

go for it, leave criticism if you downvote plz.