Sending a wall of text in an email is, IME, ~never^1 the right thing to do. If more than a fraction of colleagues fall into that bad habit, soon all anyone will be doing is email. Let alone if you try to respond to one of the too many points in an overlong message, or loop someone else into the conversation(s) which are now hopelessly fragmented. It's akin to a self-inflicted DoS attack.

1. Exceptions do exist (eg if the message is intended solely for and addressed to a single recipient, and includes a disclaimer / request / reminder about general email hygiene), but they're vanishingly rare.