I am sure it's all about what you are used to. We just returned from 16 days in the San Juan Islands (from Gig Harbor). Going up across the Straits from Port Townsend in mid-August, we followed an all night small craft advisory warning. They water was chopped up in 40 different directions with a 3-4 ocean swell off the port quarter the entire way across. Having just transitioned last spring from a 34' sailboat to a C-28 (2019), I was used to heavy water and would not hesitate to tackle such conditions. The C-28 is much more tender than the fully displacement sailboat we sailed for 16 years. The unpredictable chop required constant attention and when you tried to steer out of a large choppy wave, you would tend to put the ocean swell off the beam, creating uncomfortable roll. All in all, the Admiral was not very happy for much of it. It was a rough 2 hour ride. I kept seeking the sweet spot in relation to angle and speed, trying from 4 kt up to 13 kt or so. Nothing worked for long and it was constant steering due to the varied wave angles.
The rest of the trip was pretty calm, with only mild chop from time to time. The C28 handles mild chop very well. Coming back down the Straits were clear until we hit the tide rip outside of Admiralty Inlet / Port Townsend. It was again a multiple direction chop but w/o the ocean swell. We did well, keeping at 10 kt or so until we hit a larger than normal wave and as we hit the bottom, my helm side windshield wiper bounced off the window, became dislodged from the wiper arm and took one bounce off the deck before going into the water. At that time we were taking a lot of spray and of course w/o a wiper I could not see very clearly - the Admiral stepped in and help us get out of the chop into Port Townsend. Not sure if it was not properly installed or defective, but since I'd just installed the wiper blades before we left, I'll vote for defective rather than not properly installed. The one that failed was a Rain-X product (I followed some of the recommendations off this site) and I installed (from Port Townsend West Marine) a Marinco which based on observation and short term use, looks like a better product. The 24" blade fits fine and covers more ground than the 22" Rain-X.
The bottom line: we are not ready to start using the back door to the San Juans (up the east side of Whidbey Island and either Deception Pass or the Swinomish Slough (La Conner) and will continue to take the fast route via Juan De Fuca, but will probably take extra time, as necessary, to avoid heavier chop conditions such as we encountered. I do think the new C-288 with the ten foot beam will handle rough water better than the 8.5 foot beam C-28. I also won't forget that the worst thing you can have on your boat is a schedule...