The thing is, you apparently to switch to an airline that makes redeeming miles to a place like Bora Bora a bit easier, right?

Redeeming to a place that the airline doesn't fly themselves and where you have to search all sorts of partners is always going to be much harder.

So the only way to make it easier is to choose the destination you want to go to and then figure out which airline will be easiest for that destination.

And also be aware: Easiness is often inversely proportional to cost!

The easiest flights on an airline are those on its own metal the whole way if you're willing to pay double. You then can book at any time, get any seat that's open, etc.

Everything else is more complicated, because of the capacity controls. Capacity controls are not better at other airlines, and they're no better when dealing with partner airlines at other airlines.

So does any airline that flies out of your home airport fly its own metal all the way to Bora Bora (or wherever else you'll want to redeem next time)???

Finally, you say you hoarded miles for many years before redeeming. Well, keep in mind the ease of booking awards at different ailrlines can change from year to year! (For example, it might get easier to many destinations on AA if/when aa.com adds oneworld awards. Currently you can't book awards on aa.com unless they're all the way on AA metal, but AA has said they're working on being able to book awards on BA/IB/etc metal later.) If you're not going to redeem for many more years, you have to guess which ailrine it will be easiest to redeem on then, not which one is easiest to redeem on now!!!