Chat windows: This will cause problems, and no need for this. If you're in a party, running a dungeon and ure chatting wwith ur guild u have to switch the whole time. Also the /g and the /p aren't problems for me.. But that's my opinion

Guilds: Why would u ever wanna customize guild ranks? No need for this, but maybe a rank between officer and recruiter: 'Good member' Cant get kicked by an officer and is able to recruit. The rank system is a bad idea. Do u think players will be happy if they are one of the lowest player in the guild? No.
But the new themes that u can collect with ur whole guild is a good idea