In my opinion Rose Lover should be limited. Sylvan is so good with the OTK because Rose Lover can quickly summon the big boss to the field when she was milled almost immediately every turn. At least it reduce their powercreep otk capability to manageable level.
Nerfing Rose Lover will afect every plant deck such as aromages which are not that bad to deal with considering how inconsistent currently is. Just nerf sylvans, lol.
Magical Merchant isn't even necessary in a Sylvan deck. I used to run my deck without it and it worked just fine. Leaf and Shroom should either be semi or limited.
Well to be totally honest there are Sylvan deck that is out there that still operate well even with one or two Kumoshroomo. I do believe that Rose Lover and Marshaleaf is the lethal card in the deck those two summon big or destroy the big. So in my opinion both need to be limited to 1 and Aromages don't really rely on Rose Lover that much they have Jasmine so wouldn't affect them much.