Would it be possible to put settings generated by wacomcpl in a file ~/.wacomrc instead of ~/.xinitrc? Then this file can be sourced from ~/.xinitrc by the user. Alternately, wacomcpl could add "source ~/.wacomrc" to ~/.xinitrc, so the user will not notice any change.
Motivation: Some users (e.g. me) have complex ~/.xinitrc's. The reason being I run it on multiple systems with vastly different installations, hardware, etc using the same settings. Messing with this file in an automated way might break something (as it did in my case).
Mainly my suggestion is the following:
1. Put all auto generated settings in ~/.wacomrc
2. If the line "source ~/.wacomrc" exists in ~/.xinitrc, then do nothing else
3. If the line "#source ~/.wacomrc" exists in ~/.xinitrc, then also do nothing else.
4. If neither of the above exist, have wacomcpl display a friendly dialogue saying "Automatically load your WACOM settings on startup? Yes, not now, never.". If the user says "Yes" then add "source ~/.wacomrc" to .xinitrc. If he says "not now" then do nothing. If he says never add a commented "#source ~/.wacomrc" to ~/.xinitrc.
PS: This is not really high priority, since users who have complicated ~/.xinitrc's generally know what they're doing and can work around any problems caused with automatically editing the file. But it would be nice to have all settings in ~/.wacomrc...