Oh goodness no! Besides the fact (as stated) that it rips the horses coat of its naturally produced oils, if I bathed my horse everyday I would be out till midnight haha!
Especially since here in N.c. The winters are brutally cold, so there is virtually not rinsing or bathing right now (which bugs me because she is always dirty).
I as well only bath my horse before a show, or on a hot summer day just to pass time and give your horse that amazing smell:)
If a dirty horse REALLLY does bug you though, try spraying your horse with a coat spray, waiting maybe 30 seconds, then brushing through it with a dandy brush. That has helped me get my horse squeaky clean (water free) for a while now:)