I believe E-Heroes might be viable when we have access to Omni Heroes. Big and Little City variants are already too slow...Gemini Spark might make Little City viable if it's released, but that's all I can think of right now. Don't loose faith, we all know Konami has a thing for Dragons and Heroes.
E-heros will never make it to the top!! it need 10 extra deck monster, Ehero shadow mist (add card) & miracle fusion/parallel fusion to maximize Ehero potential, and this is why Shining Flare exist.
Elemental Hero never be a meta deck , even we have 10 extra deck, omni-hero is bad , the only good is E-Hero absolute zero, the best hero is masked hero
The best Hero is Omni + Masked Hero.
What we really need is Stratos...Skill accesible only, add to hand/draw, once per duel..kind of like Dragon's Mirror or Miracle Fusion at the moment. :v
Prisma would be interesting, but I see it being used mostly outside of E-Hero...the card pool we have at the moment is unimpressive. Neos variants would get a boost for Miracle Contact, but it's still pretty meh. PrismaGB would probably make a splash as well.
Prisma is great for all fusion but Blazeman is very good for omni-hero and masked hero , prisma only change his name but blazeman change his attribute + add polymerization