Maaate,
I reckon that's brilliant - simple sensible and safe. Mode S transponders would make it even simpler ? but much more expensive I fear..
VFR in class E without radar is a big hole in NAS - if that Tobago had a dodgey transponder or had not operated it correctly, let's face it neither of which is uncommon, (Yes, I know that's 2 ifs and probably in risk management terms not that great - but still a risk!), one dreads to think of the possible consequences.
VFR in class E is fine - IF TCAS, transponders and pilots all do as they are supposed. .......... but there is no failsafe, other than mk 1 eyeballs, in NAS if they don't.