I believe these tweaks would fill the gap that many players yearn to be filled, as summoners currently only have 1 armor set, the lowest of any armor sets pre-hardmode.
"pumpkins are only available during Halloween!"
nope, the dryad sells them, so this set would be post-eye of Cthulhu.
"shadow scales/tissue samples seems a bit random"
they're in the crafting recipe to make them post brain of Cthulhu/eater of worlds.
"but ranger only has 1 armor set, why should summoners get 2?"
rangers have 2, the fossil set and the necro armor set, summoners currently have the least armor sets pre-hardmode, hence the need for another early game one.