Hell that's a lot of erasing

Kudos on that lol. Characters dull next to eachother isn't really my thing though. Have you tried to get them using stances and such (monk casting, warrior attack stuff like that)? There once was a wallpaper of someone who did the same as you but bulked them up, all doing something (casting, emote) some from different angles, was quite cool, maybe something for you to try next.
Besides that, I think (like you already stated) the stroke around the characters is too pixelated. I would either duplicate the layer and put a blurred one behind it (filter>blur>gaussian blur) so you get a smoother edge, or maybe no stoke but a glow around them?
Overall duplicating layers gives you the possibilty to make the quality of your characters alot better. You can duplicate and blur (behind the original layer or on front at low opacity), you can make a layer on top a different lightning setting (overlay and multiply do good, just change opacity to get the colours to your liking), also adding adjustmentlayers is a fun thing to do (layer>new adjustmentlayer> try them all

)
Really gives you some nice things, to spice your screenshots up. Not trying to get your work down, just giving you some comments that could help you and put your work to another level.