Help on Black team

Hey, I just finished 8th gym and I'm having huge trouble in whether to drop some Pokemon or train others from my pc. (I already dropped Simisear even though he served me well as my 2nd Pokemon, feel kinda bad)

Samurott lvl 47
Ability: forgot
-X-scissor
-Surf
-Razor Shell
-Revenge

Excadrill lvl 44
Ability: sand rush
-Strength
-Earthquake
-Rock slide
-Sword Dance

Scrafty lvl 48
Ability: Shed skin
-Crunch
-Hi jump kick
-Brick Break
-Dig

Archeops lvl 45
Ability: defeatist
-Fly
-Dig
-Crunch
-U-turn

Fraxure lvl 42
Ability: Mold breaker
-Dig
-Dragon Dance
-Dragon pulse
-Aerial Ace

Darmanitan lvl 45
Ability: Sheer force
-Hammer arm
-Flare blitz
-Fire punch
-Dig

In my pc I have a Bouffalant and a Tynamo. If it wasn't for Fly, Archeops would've been out ages ago as I don't see him as powerful as people say he is.

What should I do?

more than good enough to beat everything ingame (except maybe subway), just level up more.

of the 6 pokemon archeops is lousy due to its crap ability
and samurott is average at best with better water types out there (but BW has a poor water selection anyway).
and pls dont teach strength to excadrill you wasting a moveslot.
and dear you shld have gotten a moxie scrafty instead.

rest are good enough.

You probably have one of the most popular teams compiled there, all very strong Pokemon in different ways. If you are debating whether to switch to Eelektross from Archeops then I would recommend it because although Eelektross has a lower stat total, it's movepool is far better and with it having the Levitate ability, it has no weaknesses whatsoever whereas Archeops has five weaknesses. Both are great Pokemon don't get me wrong but in your position I would go for Eelektross.

I need to point out that you have a bit of a Water weakness going, but thankfully Fraxure's Dragon-type resists that.

Also, remember to evolve your Fraxure into Haxorus cos it's recommended you have a fully-evolved team before you take on the Elite Four.

I'll also go with these guys and say replace Archeops for Eelektross, but it's your decision.