Good points but some thoughts. Trust or respect are subjective temporal evaluations that can not be uniformly institutionalized in the form of standards and compliance that guarantee protection of rights. Companies already challenge domestic requests such NS letters and even FISA orders at great cost and legal effort while legislation and case laws change creating evolving and unsettled questions.
To impose another burden of companies to develop or hire expertise in other countries whose laws and politics also change and evolve is an excessive burden. So is making sure that specific requests are compliant every time with the proposed law.
The US-UK law enforcement data exchange Agreement (should it ever be authorized by Congress) would be a positive step in regularizing the process of cross border data exchange and preventing the balkanization of the network. Fears that it is overbroad, that UK judges lack independence, or that the UK’s law enforcement powers are not subject to review are themselves mistaken and a bit overblown. They also lack a due regard for the integrity of the UK democratic process.