Well, a round without changed typings for me, oddly enough.
Pokemon: Serperior
Typing Change:
New Stats: 70 / 110 / 75 / 75 / 120 / 68 (518)
New Ability: Overgrowth / Contrary (HA) [no change]
Added/Removed Moves: +Power Whip
Justification: Serperior depends on Contrary Leaf Storm to be threatening as it is, so gimping it appeared to be the way to go. IT also has various sets otherwise which are MUCH worse. Now, it has a highly buffed Coil set and a Dual Screen set which stil works, albeit differently since it sacrificed speed for much more bulk. The speed also allows the Contrary set to be revenged much easier, now the revenge-killers are no longer restricted to Swellow and Scarfers. Unless it carries a Choice Scarf itself, but that has its own host of issues, most notably that things like Flareon and other bulky Fire- and/or Flying types would come in and blast it if it uses Leaf Storm, and its coverage is piss weak anyway (and Dragon Pulse, while it has a ton of neutral coverage, hits little for SE too, and it is fairly weak... it hits only barely harder than a NVE Leaf Storm, even).
Pokemon: Skarmory
Typing Change:
New Stats: 45 / 50 / 140 / 65 / 70 / 70 (440)
New Ability: Keen Eye / Weak Armor /
Big Pecks (HA)
Added/Removed Moves: -Stealth Rocks, -Brave Bird, -Taunt
Justification: Skarmory, an amazing physical wall and it remains like that. NU isn't short of powerful wallbreakers, and with Brave Bird gone even Flying-weak things like Gurdurr set up all over it, even moreso now it lacks Taunt to stop it. On the physical side, you need SE coverage to bring it down with a 2HKO but it is not impossible. On the special side, it is fairly frail and it lacks Sturdy, so mixed attackers are even more dangerous to it. In short, it remained a solid physical wall and Spike setter, but it gained also a fair number of flaws that prohibit its use.
Pokemon: Ledian
Typing Change:
New Stats: 90 / 90 / 80 / 55 / 160 / 85 (560)
New Ability: Early Bird /
Technician / Iron Fist (HA)
Added/Removed Moves:[/B] +Bulk Up, +Attack Order, +Fire Punch
Justification: I decided to give Ledian mostly more bulk. While it has the stats, it still doesn't have the typing, not too dissimilar from Articuno, who has 600 BST and still resides in PU because of crap typing. Ledian isn't overly different now, having a far more desirable BST, and a crap typing. Its typing isn't really unique, being of the common Bug/Flying type, but it is the only physical attacker with said typing.
Its STAB moves currently suck, but Attack Order is the only one that remotely fits if it comes to a powerful STAB move, though I guess Technician Aerial Ace also counts... Technician Mach Punch also hits harder than Iron Fist Mach Punch, but its Elemental Punches are weaker with Technician. A choice that is up to you.
Pokemon: Ariados
Typing Change:
New Stats: 70 / 110 / 100 / 70 / 70 / 50 (470)
New Ability: Swarm / Insomnia /
Oblivious (HA)
Added/Removed Moves: None.
Justification: Another massive stat buff, mostly on the offensive department. Megahorn makes sure it can hit pretty hard, its Taunt immunity makes it can almost ensure Sticky Web getting up if it carries a Sash... get your Defogger ready!
Outside of that, it didn't really change too much. Ariados has everything it needs but lacks the stats to pull them off.
To be honest, I'm not that creative with Ariados.