My opinion of Zen is it seems a tradition that depends heavily on qualified teachers. I think the bulk of the questionable behavior we see comes from students speaking about things they are not yet qualified to speak about. I think this is not the fault of the religion itself but rather due to the wide availablity of books websites.
Conversely, Theravada seems to rely more directly on scripture which I think makes it easier for everyone to get on the same page (no pun intended) and making Theravada an easier fit with our information rich society.
I think the reality of our situation presently is that Zen in the West has relied on translated texts
(of teachings from Patriarchs and great masters) in much the same way as Western Theravada has relied on translations of sutras. Traditionally, qualified teachers were central in Zen Buddhism, definitely, and we do have many excellent teachers. But interest in Zen has expanded at a rate that teachers alone cannot provide for, imo. Perhaps this is one reason many of us are drawn to the Theravada tradition, as an exemplary group of modern Buddhist practitioners, to learn from?
If Zen Buddhism is to move forward without becoming a sloppy mess we need most probably thousands of qualified teachers and/or a better sense of what constitutes helpful texts/scripture, as well as key practices.
Speaking only for myself, while I have had contact with qualified teachers (in recent years) I've had to make my way on my own pretty much, since the early 1980s. Most helpful over that time (imo) has been to read texts from highly realized masters, both within Zen Buddhism and from other traditions.
For the last 5 years I've found that sincere practitioners
have been very very helpful, in guiding my practice, and study. This points to a third potential method for strengthening our traditions, with the existence of online sangha communities like E-sangha, Dhamma Wheel and ZFI. This is still an experiment, of course, but initial results with this ongoing experiment look encouraging, imo.