Just going to through some two cents on Scolipede:
I caught a Venipede in Pinwheel forest on my Black playthrough and it has become an asset. I use Carracosta and Sawsbuck, so the Fighting resistance is greatly appreciated. On paper, he does have a shallow movepool pre-E4 but he learns a few fun and supportive moves like Screech and Bulldoze to pull his weight around with support. There's also been a few times where his physical bulk took a good Flying or Rock attack and Swarm kicked in for a nasty Bug Bite, Steamroller, or X-Scissor.
I think he works very well when he needs to. It all depends on the team, really.
Daramantian
Samurott
Galvantula
Hah, these three are part of my first B/W playthrough on White. Everything you said is exactly how I feel about those three.
I ran with Samurott, Galvantula, Darmanitan, Golurk, Braviary, Conkledurr
Samurott is an excellent revenge killer. His bulk saved me from a lot of troules and Retaliate did a number on 3/4 of the 2nd Round E4. I use Surf / Aqua Jet / Revenge or Retaliate / X-Scissor or Megahorn. Surf is only there for HM usage and I plan on changing that to Scald when I get a chance. With the lack of Waters in Unova, Oshawatt being above the other two makes a lot of sense.
Darmanitan is becoming one of my favorite Fire-types. The sheer power of his Fire Punch makes my jaw drop every time it nearly OHKOs something that is 10+ levels higher. Flare Blitz is good for raw, unadulterated destruction, but I guess it comes down to personal choice. And it's great that Darmanitan gets so many options in that regard. He earns his position.
Galvantula is pretty much my favorite Pokemon, coming in a close second behind Nidoking. It's very simple, and very elegant, but I wish he had a bit more diversity in his movesets. But Thunder/Bug Buzz/Energy Ball is good enough, with one slot left open for preference. Very good, very very good.
Golurk is hilarious and I've had a lot of success for him so
I'd like to vote Golett be moved up one tier. Ghost/Ground is a good typing late-game, resisting Fighting and Rock while also having enough Bulk to take on a few hits from other types. He can support your team with Will-o-Wisp and/or Bulldoze. For the first-round E4 and post-E4 game, Golurk works very well as an on-hand Flyer since it takes advantage of the move in battle (switching into Fighters and stalling BRN status).
Conkledurr, as everyone knows, is a beast and has proven his worth time and time again. Strength and bulk to take on even neutral hits. There isn't anything I can say that hasn't been said.
Braviary has been worth the work so I
'd like to vote Rufflet be moved up one tier. Normal/Flying isn't a bad typing, with immunities to two types. If your team suffers from Ghost and/or Ground weaknesses, I can't think of any other Pokemon to use if you have the White Version. Maybe it's the team I had, since Braviary had a lot of synergy with my guys, but I found him to work out very well as a lead. Bulked Up Crush Claws, Rock Smashes, and Brave Birds feel viable enough to be considerd better than "low tier". Maybe I'm wrong.
I feel that the performance of the Pokemon in the game, no matter at what stage you may be, is what is important. Maybe I'm misunderstanding the tier system here, so please correct me with these votes if necessary.