Fully representative? No. There’s definitely room for improvement. We are - and will continue - working to make it more representative and independent (and I don’t expect we’ll ever stop). We have some updates planned before the next ZCAP poll, and we’re always interested in hearing Ideas for expanding ZCAP
Effective? Yes. It played an important role in establishing the Dev Fund (and the Zcash Community Grants program), and we at the Foundation genuinely take its input very seriously.
Can you elaborate on what you mean by “accessible”?
We certainly keep an eye on other platforms and channels. I’m not as active on other channels because of time constraints (I have to ruthlessly prioritize based on SNR) but others (e.g. @decentralistdan) keep their ears to the ground.
FYI, I’ve been lurking on your Telegram group for a long time. I don’t try to consume the entire firehose but I check in occasionally to see what people are saying about me and the Foundation, so I see your groans. 
What do you think we should be doing?