Spiders are really varied creatures, it'd be nice to see more! I'm actually really surprised that we haven't a particularly traditional tarantula. Galvantula is nice and all, but it's too cutesy-fied and is missing the BA black and orangencolour scheme one associates with tarantulas, and there's also the fact that it doesn't even have eight legs.
A Goliath Bird Eating Spider with an ability based around making Bug-Type moves super effective on Flying-Types (and maybe make Flying-Type moves neutral or NVE?) would be really sweet!
Also, what new Pokemon are you guys expecting from CoroCoro and/or the Treehouse stuff? I'm just expecting trailerbirb (from either source) and maybe regional rodent from the Treehouse stuff.
The spider I would want to see the most would be a
peacock spider. I find them quirky and I dare say cute with how they raises their flap and dance around.
Other spiders I think would be cool are
assassin spiders, the
diving-bell spider, any sort of spiny orbweaver(like the
crab-like spiny orbweaver or
curved spiny spider) and trapdoor spiders, preferably from the
Cyclocosmia genus.
Other arachnids I think would be cool are
camel spiders,
whip spiders and any kind of scorpion, I believe Drapion is actually a
vinegaroon/whip scorpion(although I might be wrong on that and it's just a heavily stylized scorpion), who aren't actually scorpions.
As for what we will get through various sources this month I think we might be due to our first collection of relatively random pokémon. I'm talking about something like when Gogoat, Helioptile, Pancham and Fletchling first appeared during May that year, the bird might be among those. June generally tends to have a decent amount of new pokémon, June before XY had 9 new pokémon revealed between E3 and CoroCoro, and in June before BW CoroCoro had 7 new ones alone. That's just speculation though, and they might slow down due to the blowout earlier this month, even if I think that would be an odd move.