Well, the way I used magcargo isn't by checking physical threats, it's to stop set-up sweepers with clear smog and swap-in to a predicted physical attack. For example: "I can smell that mach punch from that Hitmonlee a mile away, so I'll swap in my Magcargo, tank that hit like a boss and hopefully get a burn and some rocky helmet damage" or maybe "fletchinder has set up swords dance on my poke, so I'll take that acrobatics and clear smog to remove those boosts". Flame body has a 30% chance to burn which is as high as scald does so it does happen a lot. Either way, I do use him on my trick room team and he works better than you'd think. Several times he has stopped a belly drum slurpuff right in it's tracks and has burned several foes without doing anything but swapping in and out. You could argue and say that amoonguss works better as a clear smogger and I would agree with you, the niche that magcargo has is having flame body to punish physical attackers and he has better defenses. Either way, he has proven very useful on my team.
It gets kind of tiring seeing these kind of posts, so i'd like to say a few things:
Firstly, you need to post some kind of an actual set. For example,
Alomomola @ Leftovers
Ability: Regenerator
EVs: 104 HP / 144 Def / 252 SpD / 8 Spe
Calm Nature
IVs: null Atk
- Wish
- Protect
- Scald
- Toxic
This isn't always necessary for any discussion of a Pokemon; for example, Alomomola is fairly well-known, so I don't have to post the set every time I want to discuss it, although I might want to clarify if it's specially or physically defensive, maybe mention what move i'm using in the fourth slot if it's not Toxic.
However, when you consider that Magcargo is unranked, it's reasonable to assume that no one really knows what it does. When you're out here trying to explain how you use it, maybe you can just post some kind of actual set so we can evaluate it.
Next off, you should talk more about what threats it actually beats. For example, it's a great Fletchinder counter (moreso for killing it with Rock Slide or w/e but still). What other threats can it beat? If there aren't any, then maybe that's a reason it's not very good?
Finally, let's talk about your other points.
freddymc said:
"I can smell that mach punch from that Hitmonlee a mile away, so I'll swap in my Magcargo, tank that hit like a boss and hopefully get a burn and some rocky helmet damage"
252+ Atk Life Orb Hitmonlee Mach Punch vs. 248 HP / 252+ Def Magcargo: 112-135 (36.9 - 44.5%)
In addition to the fact that you just took a lot of damage, especially if Stealth Rock is up, you've just given Hitmonlee a free turn to keep attacking, and certainly taken more damage than he has. If you actually managed to lure Hitmonlee into using the weak Mach Punch instead of his beefy-ass High Jump Kick, jump on that train and take advantage of it! Unless you have a hard counter to Hitmonlee, in which case why take that risk?
There's also the fact that your nose might be off and you might just die to a High Jump Kick to the face, yeah? By the way, everything I just said applies to any physical attacker...unless you wall them, in which case refer back to my previous points vis a vis 'threats Magcargo beats'.
Ultimately, you're taking a dumb risk and hoping luck bails you out. Sure, there's some value in being able to roll for luck at low risk; mind mentioning some Pokemon Magcargo can do that against? I wouldn't spam Scald against Pokemon that can OHKO me either.
freddymc said:
"fletchinder has set up swords dance on my poke, so I'll take that acrobatics and clear smog to remove those boosts"
Firstly, like i said up there, why not just kill it?
Secondly, what other setup sweepers can you do this to without risking death? Mind naming some?
Belly Drum Slurpuff, by the way, OHKOes Magcargo, while healing up at the same time too, and sometimes carries Aromatherapy on top of that.
Finally, Trick Room Magcargo? I recently played with a Trick Room team, and i'm willing to attest to the fact that Trick Room NEEDS every turn it can get. Why waste those turns with Magcargo? Something like Rhyperior can still stop Fletchinder and lay waste to teams in the process; hell, give it Lum if you're worried about burns and it'll still be better than Magcargo.
Overall, what I see is a lot of 'i'll outpredict them easily' and 'i'll get lucky' which is bad policy for winning matches against players who are as good as you are.