Is CheckSequenceVerify only a stop-gap measure?
CSV is not a stop-gap solution. Before you can say that, you first need to define what the problem is.

CSV solves the problem that you can't use CLTV in contracts that need a spending delay where the output itself will not be broadcast for an unknown amount of time. This is a very abstract problem, but it does occur as a primitive inside more complex constructions.

However, the current Thunder implementation uses a stop-gap solution to transaction malleability, which just happens to rely on CSV.