I missed this post the first time around. I definitely think True Strike needs to me modified, but I'm not sure that extra damage is necessary. Personally, I've changed the target to self (you don't have to pick a target when you cast the spell, and there's really no need for that lame 30' range) and removed the verbiage about it being the first attack on your next turn (so battle magic and quicken meta-magic can be effectively applied).
I thought the action cost and Concentration requirement would keep it from being spammed by certain 'builds' that would try to take advantage of the looser restrictions, but now I'm not so sure if the concentration requirement shouldn't be removed as well. 'Dippers' that are trying to take advantage would probably not care about Concentration anyway. I think the most abusable case would be spending an action to set up a high level spell attack, or to make sure that arrow of slaying strikes home in the dragon (shades of Smaug), and I'm not sure I see anything wrong with those scenarios.
I thought the action cost and Concentration requirement would keep it from being spammed by certain 'builds' that would try to take advantage of the looser restrictions, but now I'm not so sure if the concentration requirement shouldn't be removed as well. 'Dippers' that are trying to take advantage would probably not care about Concentration anyway. I think the most abusable case would be spending an action to set up a high level spell attack, or to make sure that arrow of slaying strikes home in the dragon (shades of Smaug), and I'm not sure I see anything wrong with those scenarios.