I pulled all these comps off worldofwargraphs.com for comps above 2200+ (which I'll explain in a moment) that have a percentage of locks above that rating higher than 1%, the list you make of comps you have seen a warlock in are according to their data are all below 1%, where as all those ret comps I listed are above that threshold.
vi·a·ble/ˈvīəbəl/Asides the two conventional triple DPS setups, ret+rogue+hunter/DK, we have nothing to play asides ret/DK/priest that's able to compete for rank 1 - that's what "viable" means to me, not 2200 or even Gladiator capable. 90%+ of combos someone is even able to come up with (leaving out prot specs) are doable to reach 2200 with if played properly, no wonder rets have that many.
Adjective:
Capable of working successfully; feasible.
Unless you are saying "Rank 1 Viable", viable means the lowest requirement necessary to succeed - if you need 50% to pass your course in school, viable is 50% - which is why saying "Rank 1 Viable" is a paradox: if you are the superlative, you are not the minimal requirement for success. If I said "Competitive" that's a very different word. Obviously I don't want to look at all comps that a ret could possibly play though, so 2200+ Viable seems like a pretty solid limit this season - given there are only something like 26 teams above 2200 on my battlegroup - it's a pretty elite sliver of the arena playing crowd right now.
To illustrate this point, I'm going to addendum your list of apparently viable warlock comps below with the percentage of warlocks playing that comp above 2200+ in north america.
Of those, your right that I must have overlooked WLS (though it barely meets my 1% minimum cut-off) - but all the other comps you listed are non-existent below a margin of randomness / stubbornness to change comp. So, I'm not pulling your leg about there being lots of viable ret comps - where viable means 2200+ capable (because viable can't mean rank 1 viable) - and given the caveat I made in the first post that they are all variations on the same theme of rets with rets/dks/rogues/hunters/discs.Resto/disc/warlock - 0.73%
Resto/warlock/warlock - 0.18%
Resto/ret/warlock - <0.01% (they don't keep record of comps below this threshold and none were listed)
Resto/enha/warlock - <0.01%
Resto/feral/warlock - 0.73%
Shadowcleave - 0.27% (Frost) 0.18% (Unholy)
LSP - 0.18%
MLP - <0.01%
WLS - 1.09%
RLD - <0.01%
There's more. For sure. I can't be bothered recalling all of them but hopefully you get the idea by now.