According to a new leak from the Genshin CN community, Childe's ascension stat was changed from crit. rate (leaked in the closed beta) to hydro bonus damage.
Since his "Broken Flow" mechanic relies so heavily on critical hits, this change means that building him becomes much more restrictive without Skyward Harp or a similar bow with crit. rate stat. This also means that he will be less effective without his constellations, since he only has full hydro damage conversion in melee form.
Of course, this is all tentative until the patch actually hits tomorrow. However, if you were planning on pulling for him and/or have already prepared gear for him, you'd do yourself a big favor t