I have not found a happy medium. Either you get wet from lack of venting (personal wet) or the garment leaks and you get wet (environmental wet).

I admit some personal vanity in saying when I lived in the PNW I did best with a small ruck (or no ruck) wearing basic waterproof pants (Sierra Design, et al) and a G.I. rubber poncho or similar model. Pants kept me warm, poncho let the upper body vent. Stayed dry all over. A decent poncho requires a lack of vanity/ego that I in a crowd did not have. Because you look like a dork.

Today I have less ego so would wear that get up in a group setting but find that technology allows me to stay dry through proper layering and a light loose shell. I currently like Frogg Toggs gear. It waterproof and very light and can be very cheap (about $60 a set of top/bottom). But it can tear easy if your sliding a lot. I carry Tenacious Tape, which IMO is better than Duct Tape for outerwear fixes. At the price of that gear I own multiple sets and sizes for people in a hurry.