Uh... no. This is the kinda stuff that makes my posts sound so hostile. First, Deepseascale is mentioned in the analysis you guys seem to pretend doesn't exist. Second, look at how crappy his HP is. Yes, no Special Defense will save you from under 300 HP max. None.
One day I'll write a Defense Tier article >_>
Listen man, you can't just look at a Pokemon's HP or its Sp. Defense and say "Wow, that Pokemon is good/sucks". It is just bad logic. Indeed, Despite Shuckle's lackluster HP, Shuckle's Sp. Survivability is comparable to Bold Blissey's in a Sandstorm, while offering significantly higher Physical Defense to boot. (Similarly, Blissey's Lackluster Defense does not stop the fact that Bold 252/252 Blissey is comparable to 0/0 T-Tar in Physical Defense) The solution is of course to combine HP and (Sp) Defense together into a single number. And thats where Defense Tiers come in. I don't claim that Defense Tiers are perfect (indeed, SkarmCents/BlissCents were created to address some of their faults), but they are certainly a step up.
Plus you kinda forgot about the other, much better Water Special Wall, you know Lanturn?
Modest DeepSeaScale Clamperl hits 121.75 Sp. Def Tier.
Calm Lanturn (40HP /240 Sp. Def) == 121.70 Sp. Def Tier.
This means that Clamperl actually has slightly higher survivability than Lanturn after taking into account the DeepSeaScale. Lanturn however gets the benefits of leftovers and arguably a better typing.
Its a gimmick yes, but with it taking attacks about as well as Lanturn would on the Sp. Def side, it is somewhat viable.
Well I seem to recall Dusknoir having better defenses, a better Attack stat, and an actual movepool.
Dusknoir 252 HP + 252 Def == 121.65 Defense Tier. This is lower than Clamperl's Sp. Def Tier. Therefore, Clamperl's Sp. raw survivability is (slightly) better than Dusknoir's Physical raw survivability.
Please, do some calculations yourself before making claims.
It's not even close to par with that. It's. not. a. viable. option. Chain Chomp wasn't originally viewed as crappy, was it? Oh wait, they had these things that we call damage calcs that people put up to see how effective it is. You don't make sets by randomly throwing out half plausible ideas and then getting ridiculously defensive about them. You calculate.
He has calculated the defense tier of Clamperl. Between two people who know Defense Tiers, the defense tier is all you need to say to get a good idea of the walling abilities of a Pokemon. I'd say that is a calculation.
So, uh, it's 2 points lower than Hypno on some scale? Sorry, I don't know Defense Tiers. Show me some calcs.
As stated earlier, IMO, a Defense Tier calculation is a calculation. It tells you everything you need to know about a Pokemon's reletive walling capability. Anyway... The scale is one "nature". So if Clamperl had 2 more "natures" that increased it's Sp. Def, then it would be approxamately taking the same damage as Hypno would. (IE: If Clamperl was Calm instead of Modest, then it would be 1 tier away from Hypno).
As for a damage calculation, I'm too lazy. But if there was an attack that did 30% damage to Hypno (with those EVs), then it would do ~36.3% damage to Clamperl (with those EVs). More info in my sig.
---------
As for some notes so that no one is confused on my stance: I think the Clamperl set probably isn't too good, but for reasons other than it's Sp. Defense. The Defense Tier calculation is rock solid and definitely shows that little Clamperl has much more survivability than I thought it did.