Just to answer some of ldm's queries:
Ambipom's Low Kick hits several targets much harder (notably Mega Steelix), Ambi learns moves to beat a lot of the same checks, including Iron Tail and Aerial Ace. Sheer Force Rock Climb is about 15% stronger than Ambipom's Return, but that's not actually a huge power jump (Cincinno is hitting like 24% harder, for example). What does Sheer Force Fire Blast even hit in this meta? It's still a 3hko on Mega Steelix and is outdamaged by Ambipom's Low Kick.
252 Atk Life Orb Ambipom Low Kick (120 BP) vs. 252 HP / 0 Def Mega Steelix: 135-161 (38.1 - 45.4%) -- guaranteed 3HKO
252 Atk Life Orb Tauros Earthquake vs. 252 HP / 0 Def Mega Steelix: 114-135 (32.2 - 38.1%) -- 94.3% chance to 3HKO
4 SpA Life Orb Sheer Force Tauros Fire Blast vs. 252 HP / 76 SpD Mega Steelix: 130-153 (36.7 - 43.2%) -- guaranteed 3HKO
252 Atk Life Orb Ambipom Low Kick (120 BP) vs. 248 HP / 0 Def Solid Rock Rhyperior: 170-201 (39.2 - 46.4%) -- guaranteed 3HKO after Leftovers recovery
252 Atk Life Orb Tauros Earthquake vs. 248 HP / 0 Def Solid Rock Rhyperior: 142-168 (32.7 - 38.7%) -- 4.2% chance to 3HKO after Leftovers recovery
In terms of damage output from their coverage moves, Tauros is not
that much weaker than Ambipom, and Rhyperior is a more notable example of that difference in power if nothing else. I also presume you're using Choice Band Cinccino in your calcs, because LO Cinccino only hits like 7% harder than Tauros's Rock Climb.
252 Atk Life Orb Sheer Force Tauros Rock Climb vs. 0 HP / 0 Def Spinda: 313-370 (119.9 - 141.7%)
252 Atk Life Orb Cinccino Tail Slap (5 hits) vs. 0 HP / 0 Def Spinda: 330-390 (126.4 - 149.4%) -- guaranteed OHKO
Not that I condone any of these physical Normal-types in this meta, since they're really not worth using over other options, most notably Sneasel if you want the Speed tier while having the benefit of hitting a ton of things super effectively with dual STABs.
------------------------------------------------------------------
stay in B+
The likes of Venusaur and Flygon have hurt its standing really badly, but Qwilfish can still hold its own outside of those matchups. Between its typing plus access to Intimidate and Thunder Wave, Qwilfish can generally fend for itself while going about its Spiking business. It also has a decently wide usable movepool which it can tailor itself into several different roles, increasing its versatility.
probably up to B
Garbodor is one of the few really viable Venusaur checks in the tier, and has enough general all-rounded bulk to set up Spikes on a good variety of Pokemon. It also doesn't clash typings with Alomomola, the premier Wish user of the tier. Probably the main reason I hesitate to move it up further, or in general, is that it doesn't have as much tools as Qwilfish to disrupt the opponent with, and as a result invites in more threatening opponents than it would like (such as Hoopa and Mega Camerupt).
stay in A-
The sheer power of its Sucker Punch is nothing to mess with, especially if it manages to find the opportunity to boost (usually from you fleeing from said Sucker Punch). To top it off, it has the coverage to smack almost every Knock Off resist in the tier (and I don't mean just Dark resist either, I am accounting for things like Mega Steelix), all of which have high Base Power and are backed up by its enormous Attack stat. While this mon offers zero defensive synergy, it more than makes up with its sheer holepunching capability and occasional sweeping potential what with its disgustingly strong Sucker Punch and all.
probably stay in A-
I can see why Mane is nommed to drop; sometimes its lack of raw power and/or sheer Speed seems too lacking to justify its awful bulk. However, Manectric's access to Fire coverage is pretty huge, allowing it to to take out the likes of Mega Steelix and bulky Grasses in one move, and do massive damage to Steel-types in general, as it allows Manectric to less restricted when deciding its Hidden Power choice. Jolteon may be be able to outrun a select few threats such as Sneasel, Scarf Emboar, and most notably Dugtrio (I don't think I'm going to count Virizion here), but Manectric has a much easier time maneuvering around bulky cores, which lessens its need to Volt Switch all the time.
XL, up to C+
I've been using Gourgeist-XL recently, specifically a Colbur Berry Gourgeist-XL set with Will-O-Wisp, Leech Seed, Synthesis, and Rock Slide, and it has been proving itself fairly capable of walling threats and be annoying while performing the ocassional spinblocking. Its high physical bulk, (semi-)reliable recovery, and disruptive moves can make it tricky to play around, and Rock Slide does substantial damage to nearly anything that otherwise wouldn't mind said disruptive moves (Sigilyph, Fletchinder, Houndoom, Delphox, etc.). It's particularly appealing as a hard counter to nearly every physical Fighting-type in the tier, especially against SD Virizion which it hardly gives much of a damn about, despite its inability to beat Virizion quickly. SuperGeist still requires a good amount of team support, primarily from all the special attackers that lay waste to Gourgeist-Super here, but it still offers its bang for its buck.