My opinion, just to get back on topic, is that among all the possible reasons explaining why we have rolled with the roster(s) we've had over the last five years, the amnesty clause is pretty minor.
We haven't been a real player in free agency, so the big thing determining the makeup of our roster has been the value Danny places on our trade chips - notably Pierce, I think.
And most of the "serious rumors," if you want to call them that, involving Pierce, have involved partners and players (Smith, Barnes etc.) where the team has been pretty unaffected by amnesty, and I haven't heard anything concrete about player value in those situations being determined by amnesty considerations.
I'm not saying amnesty hasn't changed anything league-wide, it probably has. And I'm sure you can construct hypotheticals where we would've had a willing trade partner, for a player who would've really improved the team overall, if there were no amnesty clause.
But of course, you can conduct hypotheticals involving many other things too - trades like CP to the Lakers that broke down, for example, or the new MLE rules - that could have had similar ripple effects.
But without a specific example, and compared to all of the other things that have been going on, I don't see amnesty as some boogeyman that has substantially harmed the Celts.