Can I echo Ifor's remark re comments on 15squared (a few subsequent observations by others notwithstanding - in any event, if
every EV solver were to comment there on future puzzles that would be, well, weird).
The 15squared blog provides a shared view of clues, solutions (with explanations) and completed grid, along with a record of one person's solving experience, against which solvers can make comments that require no additional context to be established.
Without that backdrop, a comment, say, to the effect that "the definition in 17dn was weak" or "the cell two down from the top and three in surely needs to be shaded" is simply confusing if the person making the comment has misinterpreted the clue or the endgame.
But to say more (eg "the misprinted definition 'Kipper' in 17dn was weak" or "the cell containing an asterisk surely needs shading") on a general help thread in relation to a crossword that's probably only been available for a few hours risks giving the game away for solvers who haven't yet even reached that point in the puzzle. It also worries the hell out of others who've (quite correctly) used the definition 'Dipper' and put an 'A' in that special cell.
Also, because the closing date for entries has passed when the blog is published, the setter can freely comment (and respond to comments) without running the risk of delivering a 'spoiler' or alienating their editor.
Not only does a puzzle that generates plenty of comment on blog sites look like a healthy puzzle, but as a setter (and I suspect that I am not the only one who feels this way) I put time into producing puzzles largely in the hope of providing entertainment, and solvers' feedback is my only way of knowing if I've managed it - or not. Oh, and often the most painful comments are also the most useful (not infrequently prompting the response: "Ouch! I won't do
that ever again...").