Not really liking the ideas, actually, those items are a good idea to use as Life Orb, and the Choice items are just 4 items, and under Item Clause (I don't understand why Smogon doesn't use Item Clause), you HAVE to be creative with those items and use alternative options, for example Big Root can heal you A LOT MORE with Leech Seed (just imagine Leech Seeding something like Chansey with Big Root, pure win), and more if you have a STAB healing move like Drain Punch and stuff. King's Rock is excesive great when you use it with Multi-Hit's move, as you can with Silver Link flinch the half of time, or half 1/4 of time on avarage without Silver Link, pretty good. (With your suggestion about King's Rock, we could be able to flinch
the 100% of times with almost any multi-hit move, and guarantee 100% with Silver Link).
Shell Bell is a good item where hazards are not on play, like doubles, just see, if you deal huge ammounts of damage per turn you can heal a hell of damage, just Blizaard both opponents on the field hard while hail is up and laugh when they see how you heal a lot of your damage. It's also a good item on those Pokémon who tend to suicided itself with recoil moves, as it's rare you'll heal too much with Leaftovers. And of course, under Item Clause you have to use this if you have Leaftovers already used, and it's also good on sweepers, to prolong the sweep and make them really hard to revenge kill.
Quick Claw is good on extremly low Pokémon who wants from time to outspeed things, it was a pretty good option for an item before Generation IV as the battles were not so offensive pased, and thus, your bulky Pokémon survived more time to activate it at least one time, sometimes saving your life (for example I used a Magcargo on Colosseum with Quick Claw and Rock Slide, and factoring it's ability, it had benefits from "hax" on at least 1 turn per match - usually 1 per two turns -, burning the opponent, flinching one with Rock Slidem or just attacking before with Flamethrower, it was awesome). Raising evasion 30%? That's too OP, you know. 10%+ of accuracy is already ok, it's a decent option when you're using low-accuracy attacks with status moves, as you improve both in one shot, making sometimes it a better option than boosting your attack. (For example, you can make Hydro Pump an almost 100% accuracy move when you also improve another status move, making it more powerful than Surf boosted by Life Orb), and when you think about the 30% boost of the Zoom Lens, you can stricke almost the 100% of times any status move if your Pokémon is slow, it's a nice buff to the already debuffed as hell slow Pokémon.
Pinch Berries are already really good, and the resistant ones are good enough to make it a fantastic surprise to overcome a counter if you're creative enough. The unique problem is it's consumed, but even then, you can use this on sweepers to overcome it's main counter and just sweep the whole opponent's team, or on doubles, where it's actually really rare you survive more than 5 turns.
In other words, there are more viable items than just put Choice Scarf/Specs/Leaftovers to everything over there, and some are really great and sometimes better than just pure brute force, but know what? It's easier to just put those items on every single Pokémon and don't think about it too much, but if you're willing to be creative with the items, you can improve the efficency of your Pokémon, but, meh, too much work.
Improving booster items is a wrong idea no matter how you see it, changing stall from somewhat viable to unviable to the infinite.
- Sticky Barb - Causes damage to holder and attaches to attacker upon contact. Any suggestions?
- Destiny Knot - If the holder becomes infatuated, so does the enemy. Any suggestions?
- Binding Band - Increases power of multi-turn trapping moves.Any suggestions?
- Grip Claw - Partial trapping moves last 5 turns.Any suggestions?
Destiny Knot could have been a decent option on NU's ADV as Wigglytuff was one of the primes forces there, sadly, from Generation IV, NU is not now of underpowered Pokémon, but just rather of most of the Pokéworld weak to Stealth Rock, curse it. Trapping moves are usable options for stalling teams, but with the buff to those moves, the item was render useless, it should be buffed to at least 8 turns. Binding Band is a pretty decent option as you can deal 12% of damage each turn no mather what, and if you have Protect and stuff, you can usually leave 25% or even more of damage
against your counter, by just doing nothing, good for staliing, not sees too much us thanks to Stealth Rock, crippling about the 70% of it's users for doing anything at all, and the others are still suffering a lot as stall is already hard to do with all those offensive boosters there.