If keeping it gives us advantages in the Brexit negotiations then let’s keep it.
There are ways around it without getting rid of it.
For example, Parliament is sovereign and makes the law. However, there are often a lot of grey areas and unintended consequences that politically activists can exploit via the courts.
When that happens, Parliament could just update the law to prevent that loophole being used again.
Yes, it’ll be like Whack-a-Mole, but there’s nothing to stop us. We could neuter the ECHR without getting rid of it.
Therefore, keeping the ECHR is, to me, not a biggie.