Characters that do their damage from assisting are maybes.
Tanks that counter-attack are strong characters for such a mod.
Characters that take turns b/c of TM jumping instead of racking up speed the normal way are also strong characters for such a mod, if they benefit from health.
So... think about General Grievous. His kit is entirely based around health (ironic, as a cyborg, but there you go) AND he gets bonus turns when his allies are killed And on top of that, you want him to take fewer turns than your B1s until you start getting bonus turns, so at the beginning (before he's gotten his stats to ramp up) a slower GG is good.
Now, it's not absolutely perfect for GG. There's still the Defence set bonus, of course, but it's still a decent mod for him.
I'd put it on a tank who has TM jumping, myself, and look for a Health Set/Health Primary mod for Grievous.
But in general, **most** characters that get TM jumps benefit more from some other primary than speed. (But of course whether or not you get bonus TM often depends on your leader, so you can mod that way, but be aware that if you put them under another leader and they lose TM jumping from that the lack of speed might be a disadvantage there.)
This particular mod, since it's not all one thing or all the other (meaning it's got both Defense and Health in two key locations instead of having both the same) should be put on a tank that gains TM jumping rather than on someone with special kit features that emphasize health.
Finn is a decent choice, but not a perfect one. I think the best choice for this mod is 9th Sister (the Inquisitor) with Royal Guard being a good 2nd.