I have terrible problems with any 'broken' accent, even Irish/Scottish but that's just me, I would never walk out in intermission because I feel that every performer tries to give of their best but of course, Reg, he is entitled to his opinion, I wasn't knocking that, it's just that I fear that when people walk out, it can't do the production any good.
Also, I feel sure that most people know the storyline of Evita by now and would be able to follow it regardless of an accent .....just my opinion
All problems are man made and so, can be man solved.