[LIST]
[*]Absol: Hits pretty hard, gets Night Slash pretty quickly iirc, gets Superpower by tutor, Swords Dance when you catch it, and Psycho Cut eventually. A bit frail, though. [B]Mid[/B] seems good.
[*]Audino: Although I can't say with sureness that it's bad (I had fun with Dunsparce after all), I'll say that it's bad. It has consistent STAB from the second you get it, but it's not the most... optimal... candidate for a teammate considering that its Attack is originally OK but gets worse with time. Has Regenerator, which is cool. [B]Low[/B].
[*]Banette: It has 115 base Attack and its best STAB once you get it (you should have gotten the Shadow Claw TM in Celestial Tower) but outside of that it's kind of meh. It does have a lot of priority moves and Will-o-Wisp, I guess. It's slow, frail, and not overwhelmingly amazing from what I'd assume. [B]Low[/B].
[*]Basculin: The 31 IV trade Basculin from last game is gone so you're stuck with this one. It comes underleveled after you get Surf, so have fun with that, I guess. It has nice STAB with Adaptability, which gives it a neat priority move and a strong STAB. Outside of that, though, it's... not very interesting and rather frail. [B]Low[/B].
[*]Bouffalant: It comes in the last seconds of the game, but does come at the fantastically high level of 56, which is just a few Proteins away from being able to tear apart good portions of the game, I'd assume. You're not using this against anything but the Elite Four, but it seems that it wouldn't do terribly against them. Still, [B]Low[/B] for the incredibly late arrival.
[*]Braviary: I've heard good things about this mon. It seems pretty ok, actually, given that it start out with a bunch of nice moves and continues to get them throughout the game. It starts with Hone Claws and Aerial Ace (and can be taught Return and, if you want, Rock Smash instantly). Later, it can be taught a variety of weird TMs to improve its coverage (Shadow Claw and Rock Slide in particular) and also gets Fly for strong Flying-type STAB; in the lategame, it gets Superpower to finally complete its moveset and get Roost if you want it. Seems genuinely okay and held back by, if anything, its only OK speed. Probably [B]High[/B], to be honest (if I thought Unfezant was good enough for Mid, this thing should be higher).
[*]Buizel: It's kind of like Basculin++; catch it at a high enough level and you get a pretty nice STAB in Aqua Tail to go with it. It can be tutored Ice Punch and evolved instantly after that if you want; Dig and Return can also be stuck on it for more coverage. Pity that Bulk Up wasn't moved to its level-up, though. Eh well. Probably [B]Mid[/B].
[*]Buneary: I remember Stellar saying that this thing was pretty OK on IRC; it has nice coverage, at least. Probably [B]Mid[/B] given its early STAB, Jump Kick, and a bunch of other random moves it can stick somewhere.
[*]Castform: I'd imagine a Rain Dance set is optimal with Weather Ball / Scald or Hydro Pump / Thunder / Rain Dance. Still, I can't see this thing being... overly good.[B] Low[/B].
[*]Clefairy
[*]Combee
[*]Cottonee
[*]Cubchoo: It comes right before Skyla and has a good chance to come 1 level from Icicle Crash and evolution, which actually seems pretty ok. Not the strongest mon, but it has passable bulk. Upon evolution, it can be Heart Scaled Superpower and Aqua Jet; you should have the Rock Slide and Dig TMs at this point if you want to teach it those moves. Doesn't seem too bad given that it has a reliable STAB almost from the start. Does great against the next two gyms, too, and I'd imagine it does well against some of Iris' mons. [B]Mid[/B].
[*]Deerling: It doesn't seem that bad; I'm not sure when you'd get optimally, though. Getting it before Clay seems ok (it can get a lot of experience) but getting it on Route 7 seems to be useful given that it's one level from evolution. Anyway, it's pretty set moveset wise once you get it; although it's waiting for Horn Leech, it starts with Jump Kick / Take Down / Leech Seed / Faint Attack if you get it at the right level, which is a decent moveset. Return is good eventually and Horn Leech / Nature Power come a bit later on. [B]Mid[/B].
[*]Delibird: Do I have to explain why this is [B]Bottom[/B]? Awful stats, typing, STABs... Hustle is pretty bad when you don't have Aerial Ace at least (I'm aware that it can be strong, though). You get it late and you literally have to tutor it moves. Its greatest occupation is as an entertaining Fly slave; it's probably outclassed by Golurk in that regard, though.
[*]Ditto: See above; it is only as good as its opponents and, frankly, they all suck. Its low HP doesn't help when you can't EV train.
[*]Drifblim: I've heard that it's kind of underwhelming; although you get Acrobatics, Will-o-Wisp, and Shadow Ball when you get it, it doesn't get much else, from what I see. Still, you get Minimize by tutor (which is pretty cool) and eventually Baton Pass, meaning you can cheese a lot of major fights by just getting up to +6 on something stupid and then passing to something more threatening. It levels up slow as fuck due to the fact that it's in Fluctuating. [B]Mid[/B]'d be my guess.
[*]Druddigon: Where do you find this ?_?
[*]Dunsparce
[*]Dwebble: It's not the strongest but it gets a bunch of neat setup moves, attacks with decent power, and is a pretty good mon to cheese most battles once it gets Shell Smash. [B]Mid[/B].
[*]Elekid
[*]Elgyem: It's strong, but it's slow as all hell and has little but Psychic-type attacks for a bit. [B]Low[/B] just because everything will outspeed it, meaning it's always forced to take a hit.
[*]Emolga: [B]Bottom[/B]; trade it for the Gigalith instead. It has Acrobatics but nothing else; this runs off of shitty base 75 attacking stats. Its typing is cool but it's a weak mon.
[*]Espeon: It seems strong. It's (unfortunately) unlikely to get all the way up to max happiness before level 21, meaning that it doesn't get STAB moves until after Clay, which is pretty awkward. Still, I'd assume that it becomes pretty good once that happens (hell, you might as well keep it an Eevee for the sake of STAB Adaptability Return). Probably [B]High[/B] given its really good sweeper stats.
[*]Ferroseed: I think this is pretty much the only Pokemon (oh, and Steelix) that can actually hold a power item / Macho Brace and use it for all of its effects. Gyro Ball is pretty strong STAB (I remember that it was about as strong as max invested Aggron Iron Head at max power, which is pretty scary) and Macho Brace will make Ferroseed gain EVs faster, obviously. It's nigh unkillable and one of the few Pokemon that can legitimately take on Iris' Haxorus. It's slow as fuck, though, and for that it should be [B]Mid[/B].
[*]Foongus: It doesn't get a single decent Poison-type move, meaning it's stuck with Giga Drain for the whole game. Its bulk is good and its attacking stats are decent fully evolved, but it's a pretty crappy mon with nothing but Synthesis, Giga Drain, Toxic, and Growth to its name.
[*]Frillish
[*]Gligar: It's screwed out of evolution until you get to Victory Road, which is unfortunate. It's an OK mon until then, I guess. Starts with STAB (Dig) and gets Swords Dance later. Will wall Drayden and win eventually. [B]Mid[/B].
[*]Golurk: It's decent but not amazing, I'd assume. Comes late but seems OK; comes with EQ, Shadow Punch is tutorable, Drain Punch is tutorable if you have the shards, and Fly goes in the last slot for coverage. Slow but strong; does well against Caitlin and Marshal. [B]Low[/B].
[*]Gothita
[*]Grimer
[*]Heracross
[*]Jolteon
[*]Karrablast
[*]Klink
[*]Koffing
[*]Lapras
[*]Litwick
[*]Lunatone
[*]Magby
[*]Maractus
[*]Metang
[*]Mienfoo
[*]Minccino
[*]Nosepass
[*]Numel
[*]Onix
[*]Panpour
[*]Pansage
[*]Pansear
[*]Patrat
[*]Pawniard
[*]Pelipper
[*]Pidove
[*]Piloswine
[*]Pinsir
[*]Purrloin
[*]Rattata
[*]Remoraid
[*]Roggenrola
[*]Rufflet
[*]Sandshrew
[*]Sawk
[*]Seel
[*]Seviper
[*]Shelmet
[*]Skarmory
[*]Skitty
[*]Skorupi
[*]Sneasel
[*]Solosis
[*]Solrock
[*]Spheal
[*]Spoink
[*]Staryu
[*]Sunkern
[*]Swablu
[*]Tangela
[*]Throh
[*]Timburr
[*]Trubbish
[*]Tynamo
[*]Umbreon
[*]Vanillish
[*]Vaporeon
[*]Venipede
[*]Vullaby
[*]Woobat
[*]Yamask
[*]Zangoose
[*]Zebstrika
[*]Zubat
[*]Zweilous
[/LIST]