This trick is only for user, like me, where wow doesn't save the 1920x1080 resolution.

What I have to do?

Just copy your current config and write a little bash-script.

Why do my resolution gets overwritten?

I noticed, that my resolution I entered in my config.wtf gets overwritten every time I start wow.
It have something to do with the gxRefresh-Setting.

The Steps:

Step 1: Copy your Config

Make a copy of your Config.WTF (in $HOME/World of Warcraft/drive_c/Program Files/World of Warcraft/WTF) and name it for example Config.WTF_1920x1080

Step 2: Edit the new Config

Remove the lines beginning with "SET gxResolution" and "SET gxRefresh"
Insert the following line:

SET gxResolution "1920x1080"

Step 3: Write a new starter

I prefer to start my wow using the ALT+F2 combination (or per terminal) so I create my script in /usr/bin

I'll call my script "wow" - this is my content of /usr/bin/wow:

#!/bin/sh
WOWPATH="$HOME/.cxoffice/World of Warcraft/drive_c/Program Files/World of Warcraft"
cp "$WOWPATH/WTF/Config.wtf_1920x1080" "$WOWPATH/WTF/Config.wtf"
exec "/opt/cxoffice/bin/wine" --bottle "World of Warcraft" --check --wait-children --start "C:/users/Public/Start Menu/Programs/World of Warcraft/World of Warcraft.lnk"

Note: the exec command is the standard start command which crossover use!

Explanation: The script overwrites your Config.WTF which includes the settings which makes wow start in an other resolution than 1920x1080. After it overwrite your Config.WTF with the settings you want, it starts wow like crossover would do it.