After thinking about this for a while, maybe the idea that people were talking about in another thread is exactly what is needed here. A third "passive ability" for all or most ships. Maybe the Dan Noth doesn't get a passive ability, because it's proximity torpedo weapon can deal with a fast ship at the edge of the map, and it has that awesome repel that is worth 2 abilities on it's own. Any ship that has a problem with a fast ship staying at the map edge gets a passive ability to help it deal with that, any ship that can already deal with it get's a passive ability to add more flavor to what that ship already is.
I have the impression that the Scyrve is a very important race, like the Ur Quan of this game, and it has a big problem with a fast ship staying at the map edge. But, since it is supposed to be the big, imposing, scary, extra-powerful big ship... it shouldn't be humiliated like that! So it's passive ability is "inter-system warp" in Star Trek terms (or a "HyperWarp Skip" in PDU terms:-)). Whenever the enemy is beyond a certain distance the Scyrve ship begins to "glow" (i.e. power warp drive), and after whatever "glow/delay" is decided upon... it simply warps out from where it is, and warps back in within gun range of the enemy ship. This makes it probably better for the fast ship to just stay within engagement range, rather than get "jumped on" by trying to separate for an extended period. It also makes the Scyrve that big, mean, extra-powerful ship it is supposed to be.
Passive abilities for all, or most, ships can both solve this problem for the ships that have it and add more flavor to the design of all of the other ships that don't have a problem with this. Add more as you fix the problem, instead of settling for "band-aids and string" that detracts as a "compromise" to fix the problem. What can I say... It's A Kind of Magic;-)