Okay, well... The first thing I'm noticing are the EVs. I get the feeling you took a bunch of non-EV trained Pokemon and calculated their EVs. Sorry, but that doesn't work. Generally you want 252/252/4 spreads unless you have a reason to do otherwise, I.E. to outspeed a specific threat or survive a specific attack.
The next thing I noticed is that you're using everything wrong. There's literally no reason to use Specs Milotic when Specs Politoed or nearly any other Water Specs user hits way harder than it. Politoed has the unique quality of bringing permanent Rain to your team. In fact, to look at it, I'd recommend SpecsToed as a start.
Politoed @ Choice Specs
Modest - Drizzle
252 Sp. Atk, 252 HP, 4 Sp. Def
-Hidden Power (Grass)
SpecsToed's Hydro Pump in the Rain is probably one of the hardest things ever to switch in to. Some of the bulkiest things in the tier are 2HKO'd by it easily. Focus Blast lets you win weather wars with Tyranitar, nailing non-Chople TTar for an OHKO even if Sand goes down instead of Rain. Ice Beam is mostly a filler but it hits things like Dragonite hard. Hidden Power (Grass) is almost solely for Gastrodon.
Now... Dragonite should be running Multiscale, Jolly, and 252 Attack / 252 Speed / 4 HP. Extremespeed over Aerial Ace, nothing not named Scyther should ever use Aerial Ace. I'd say Earthquake over Thunder Fang too. Oh, and if you do run DrizzleToed, I'd replace Fire Fang with Waterfall to abuse the Rain effectively.
Luke's Special sets are pretty lackluster, try Dual Priority Lucario.
Lucario @ Life Orb
Adamant - Justified
252 Attack, 252 Speed, 4 HP
Sword's Dance instantly skyrockets your Attack to nearly unmatched levels. After that Extremespeed + Bullet Punch abuses priority pretty well, with Close Combat to hammer Steels that resist the combo.
I don't think Serperior should ever even be touched until Contrary Serperior is released. Even then I only see potential for Scarfed Leaf Storm spam. If you want a Grass type I'd definitely say your team could benefit from a FerroCent core, starting with Ferrothorn.
Ferrothorn @ Leftovers
Relaxed - Iron Barbs
252 HP, 168 Sp. Def, 88 Defence
Typical Support/Wall Ferrothorn. Thunder Wave slows down fast threats, which your team would love because it's mostly pretty slow. Leech Seed + Iron Barbs whittles away at your opponents health while simultaneously healing you. Spikes gives you some extra hazards, and Power Whip is when you need to hurt something.
Spiritomb is meh. No recovery and only decent stats, with typing that gives him almost no resistances makes him a pretty poor defensive pivot. Jellicent would keep similar synergy, abuse the Rain, and complete the FerroCent core, which is like the 5th generation's version of SkarmBliss.
Jellicent @ Leftovers
252 HP, 252 Defence, 4 Sp. Def
Pretty standard physically defensive Jellicent. Toxic cripples opposing defensive Pokemon while Scald keeps pressure on physical attackers. Recover keeps Jellicent around for a while and Substitute really just blocks out attempts to Toxic it.
I'm not a fan of Rhyperior, but if one must use Rhyperior, it should really be a Double Dancer... However, Rhyperior hates the Rain, so I'd look into other options. Tornadus-T, Keldeo, and Starmie immediately come to mind.
Hope I helped a bit.