I don't see an issue with it personally, though as the others have said to make the aspects sticky you would have to pay a shift for each aspect just like it's three separate spells (if it was sponsored magic then I'd allow it just as you've written it, as they can cast thaumaturgic spells at evocation speed).
The only thing I'd say on the wording is that I wouldn't worry about specifying the consequence as '-2 to athletics'. I would simply treat it as three sticky aspects at +3 (opposed by athletics I imagine), each with a free tag plus further invocations and compels available with fate points. This way, the same spell could also be used to speed someone up as well as slow them down, this is potentially much more useful.
I don't think it's broken, simply because a 10 shift attack is far more lethal. Weapon 10 is crazy and, I assume with a high roll to control and target the spell as well, it could do some serious damage. Compared to three free tags, it's far worse. Especially as the roll to oppose the tags is far easier to achieve, potentially wasting the entire spell.