i support zeb's rotom-s, charizard, sawk, and bastiodon changes, but i don't think you need to replace armaldo for anything. instead, i suggest running swords dance lum berry armaldo
since it beats common spin-blockers such as misdreavus and golurk, while your current set does not.
since you're now using rotom-s over rotom-f, opposing hail teams could be really annoying for you to face. to fix this, you can try using the standard rain dance sweeper
set on ludicolo. after snover is killed—which isnt hard hard to achieve with armaldo, sawk, and charizard—ludicolo can cancel out hail with rain dance and proceed to devistate the opponent's team. you could keep leftovers on it like your current set, but life orb
helps you grab important ohkoes on pokemon such as regirock.
summary of changes:
zebraiken's rotom-s, bastiodon, sawk, and charizard suggestions
armaldo —> swords dance spinner set
ludicolo —> standard rain sweeper set