Ephemeral Bolt deals Wil+4/Mystic Damage, and also has a -2 Willpower debuff that lasts 2 rounds (base duration), +2 per additional success.
True Ephemeral Bolt deals Wil+1/Mystic Damage, and also has a "-2 to next sensing test" debuff. This debuff doesn't affect every test, thus doesn't have a duration and we default back to a duration 1 round for the damage.
The stats are consistent with the other spells in 4E. Note also how well this works as a 1(True)-2(Ephemeral) combo, and how that sets up further actions that target Willpower.
As to the sharing of the spell matrix, I'm cool with that being a in-setting Secret tied up with Illusionism. I really like what that gives Illustionists. There are also a bunch of other Secrets scattered around the setting (the t'skrang Engineer Cult knows how to build steam engines, for Upandil's sake).
Mimicking another spellcaster Discipline was possible for higher circle Illusionists in earlier editions, and they do get "phantom" versions of a few good Elementalist and Wizard spells in 4E. I filled that gap with magic items like the Crystal Spell Box, as I mentioned. There is definitely design space here for 4th edition, and I'd like to look back to the 1st edition material again to see what we can do there. I notice that the Fists of Rage(s) haven't been updated, and in fact the True/Ephemeral Bolt combo is the only one we've seen so far. I've always wanted to make a martial-artist Illusionist because of that unarmed combat buff spell(s).
But I think that's the key for Illusionists. Find a niche with your powers and spells, and it won't look anything like the other 3 spellcaster types. Fixer, face, charlatan, musician, juggler, clown, acrobat, tactician, merchant, spy. Adepts don't walk around with a name-tag that says "Hello, I'm an ___ILLUSIONIST___" (especially the illusionists!), though it may be easy to tell some-one's Discipline sometimes. So, find a secondary skill-set, and play that to the hilt. Be both .
