As I've said before, the last time I was active here was 4 or 5 years ago, that's also the last time I was real active in map making. Anyway, back then, you were flamed if your maps were symmetrical or used weird terrain except for aesthetic purposes. I was looking through the maps here and they are all symmetrical. I also noticed a lot of Xel' Naga structures blocking paths. I looked through stickies and I found reasons for symmetrical maps but not really why or when the mentality shifted, I didn't find anything on the terrain or temples though. I figure I better post this before I post a map and invoke the wrath of that one guy for doing something wrong. Thanks.

Symmetrical maps are more balanced, basically. It's possible to balance an unsymmetrical map but harder.

As for ramps being blocked, that's for adding concept to the map/making it less boring. It means it takes longer before an expo is taken or can be used for defence.

Quality Control Now In Effect
Melee Mapping VIDEO Guide!!
Melee Mapping Section: What you should know!
Melee Mapping Guide

Don't even think of posting a melee here without reading every word in all of these topics.

I did, and I said that.