I agree... it's so annoying trying to cast shield on yourself as Oak in a wave of creeps. Too confusing and can often times result in stupid deaths all because you couldnt find your demigod in the field of battle. Yes you can see his shape but, uh, when you're fighting Giants its hard to make out Oak.
You can hold on to "Ctrl" and that will filter off creeps from your spell target selection. Even if many Demigods are clustered, yours will have a teal border, making it easy to distinguish. I used to wish to be able to self cast using the portrait as well, but found it unnecessary after a while. Moving the pointer away from the main screen to the portrait and then back also takes off precious amount of milliseconds, which can make a difference in a hectic situation.
Since there's a hotkey for selecting your own Demigod, why not have that be the self cast button too? So targetting yourself, as Sedna, with a heal might go like this: Press hotkey for heal, then press H (demigod selection hotkey) to target yourself immediately. This can be done in a hurry and frees up your mouse movements to concentrate on other stuff in the meantime.
