I saw a few nearly-identical looking nymphs in there, yeah, but I don't actually think that's correct - the head shape's wrong, IM-decidedly-amateur-O. I have no idea if that's technically an identifying feature or not, but I had several fork-tailed bush katydids hanging out on my property last summer, and this does not look like one of those. Please excuse my decidedly non-technical terminology here, but in the fork-tails (and browsing through the images in that genus, I think the rest their close relatives, too), the "forehead" sort of area comes to a point between the antennae, and the top of the head is flatter. In the nymph in my photograph here, the head is rounded - no point.

The banding on the antennae looks pretty different on all the Scudderia nymph images. That seems to be the only genus of katydid nymph that ever gets an ID...

(edit)

I looked through those more carefully, and there is one image that looked similar to this one.

See the Balabans' note--possibly a Stilpnochlora?

but didn't look at comment, so MAYBE (near) here?

The body shape, proportions, etc, look right, but the colors are different - green and brown and pale yellow, as opposed to bright yellow and aqua and black and white (man it'd be so much fun to photograph one of those . . ) - also the range of the Giant Katydid is listed as Florida. I'm in Pennsylvania.

At this early stage, it is very difficult to get even to genus with these. They "grow into their legs," so you can't go by proportions on the early instars, at least not very easily. My suspects are Microcentrum and Amblycorypha, with leanings toward the former. Makes some degree of sense, as the giant katydid is more closely-allied to the angular-winged katydids....

Good call re: difficulty of identification . . . either I've got multiple species hanging around (which is always possible, I'll grant you), or I was totally wrong, 'cause here's what I found on my little oak sapling this evening: Maybe a Drumming Katydid?

Note ginormous ovipositor, ruling out Microcentrum or Amblycorypha, at least according to the key that someone linked to somewhere up this thread.

If they are in fact little Drumming Katydids, they're likely this critter's offspring.

I know I can't say definitively that one of my earlier-photographed little guys turned into this slightly-larger gal, given I didn't actually see her molt . . but if I end up with lots of these as the season goes on and the smaller stripey ones vanish, I'm considering it a fairly good bet.

maybe it's some other kind of false katydid (Phaneropterinae). Since you've got five subfamilies to choose from in your area, this could be a useful lead. Guess you'll have to raise 'em to be sure though!