Would better location tracking for airliners improve safety?
Would better location tracking for airliners improve safety?

Very simply, no.... us knowing where AF447 was would have made exactly zero difference to the fact that it crashed into the ocean at 400+ knots.

Would we have had a better idea of where to find it? Most probably. Would it have saved any lives? Absolutely not.

As always, these things come down to cost-benefit, and the simple fact is that GPS tracking would prevent very, very few accidents. The only possible benefit would be that it may help us find the black box or wreckage, assisting in the investigation which may just possibly reduce the chances of a similar accident occuring in future. Note that of the two examples you gave, though, only MH370's black box hasn't been found (yet)... so even this benefit is tentative.