Tis is not actually expressing an opionion here, but just wanted to clarify to tabun on ferro--tehy wrote the pokes LEFT after eliminating those bothered by STABs and twave. So he meant that the only pokes that truly can come in on ferrothorn with impunity and do a lot of damage are breloom, celebi, scizor, heatran, rotom-h, and thundurus. And to be fair, luke can take ferro's STABs, but it doesnt enjoy twave--it has no hope of sweeping when it has to rely on espeed for everything. I really do like luke though, especially on deo-d teams, when paired with a dragon to form a double sweeper combo that works really well with hazards.
I used slowbro a bit in DW and it was extremely impressive. The moveset I ran was something like:
Flamethrower / psyshock / ice beam / toxic
It's kind of weird, but it allows it to do a ton of stuff. With the right EVs, flamethrower 2HKOs ferro outside of rain, while hitting genesect on the switch. Ice beam means that slowbro also functions as a great dragon counter. Psyshock lets it check Keldeo and terrakion, as well as other fighting types. Toxic is really useful for other bulky waters, and for having something to do to stuff like mamo or something. I didn't find myself missing slack off too much, since You can just switch out and regain health, and with that coverage bro doesn't need more than one or two turns to KO its targets.