As an avid UD Spider player allow me to state that I think the following would make things better: 1. Make everything in the "Spider" theme have race Spider instead of Arthropod. 2. Make all the Spiders have Web based abilities in place of CnC 3. Make Web only allow free movement by Spiders rather than Arthropods The reasoning is that web is a central aspect to spiders but has no identity with Scorpions or Cicadas or Crabs. Make it unique to the Spider theme, expand it a bit so that it's closer to a proper terrain module. EDIT: Additionally, so that it really makes them a coherent theme, add some spell/equip support. For example maybe Mass Web could do this: 50 Nora AOE 5: Affected spaces are Web. Opposing champion take 2 physical damage for each Spider in the affected area. Make Weaver's Spider Frenzy ability instead be: Spider Frenzy - (AP: 3, CD: 4) Friendly Spiders occupying Web terrain get +1 DMG and gain 3 AP until end of turn. There are other runes that could be modified to support this like Arthropod Frenzy (spell) and maybe we could give them Widowmaker. These numbers I just pulled out of thin air and are entirely likely unbalanced but just some ideas of where you could go with it.
Having more web based stuff for spiders would definitely be interesting. As it is now there is pretty much nothing being done with web mechanics which is a shame.
Not saying that the SL Insects (assuming that's what you're talking about) shouldn't get some love bc I don't hate them either (I've built some fun UD/SL Arthropod builds).
Thing with UD is that if a unit is not a demon, it either needs to be very good or be in a theme that can compete against DeP.
I would argue that Spiders can more than compete. I've run them as my main UD BG for years with some success. Also, it's not like she lost relocate but DEP did lose Shatter which hurts her toolboxiness.
While I'd like to see more web terrain than currently available, I also think there needs to be a limit in how prevalent it becomes. Anyone old enough to remember STs terrain control with impeding snowstorms and snowfall from snowchargers will remember what a horrible slog those games could be.