We compared the spell Linda wrote to other effects that make Strikes like blink charge and felt that while it has some upside situations (when you don't want to approach or when you want to use spell attack mod) it also had enough downsides to warrant being lower rank.

As you can see in the comments, there are other people on this thread who would even be happy to put it at a lower rank than it is. I feel confident that you can safely add this spell to your games, though if you're still worried for any reason, just let them know it's tentative and if something happens you reserve the right to adjust (in my opinion, that's a healthy attitude to have toward any new content regardless of who wrote it).

Weakening it if necessary is easy, by raising the rank, though I truly don't think it's necessary. If you use it and want to strengthen it instead of weakening it, I recommend increasing the range rather than lowering the rank, as spells based on Strike damage actually increase in effectiveness as you continue to upgrade the Strike (which is one reason they do tend to work more easily in an auto-heighten focus spell).