Dim, better to get in the habit of nulling now. If you ever get to the point where you make incredibly elaborate, complex, beautiful maps, the nulling could make all the difference.
And if you say you'll never get to that point, just stop mapping now.
And don't act arrogant and sarcastic in response to constructive critisicm. Face it, in comparison to half the mappers on this site, you are very, very sh*t at mapping. They know what they're doing from lots of experience, and you should take their advice on board. Have you seen Huntey's WIPs lately? If he gave me advice, I'd take it in an instant.
And maybe it was just worded weirdly, but what you said about func_walling sounded pretty unhealthy for a map.