One possible consideration is that while the main European human rights provisions are separate from EU legislation and organisations in principle, membership of the EU does require being a signatory to the ECHR under the Maastricht Treaty. Unless there is a very significant element of Cameron's deal that is getting remarkably little coverage so far, there doesn't seem to be any proposal to change this as a result of the recent negotiations.
This creates an interesting political minefield for the UK's current Conservative government, since their stated policy is to abolish the Human Rights Act (the current UK legal foundation for respecting the ECHR) in favour of a British Bill of Rights, yet as of today their stated policy as a government is also to campaign to remain in the EU. These policies seem to be incompatible under Maastricht, not to mention almost polar opposites in the underlying philosophy they represent.