The no-ad game was just an odd suggestion. But, remember, TB at 12-all does not exits otherwise also. In fact, no tie-break in the fifth is already an exception in itself.
Most people complaining about this are journalists, who surely have links to TV stations, who complain about their messed up schedule. I generally completely ignore what these people have to say, but in this case I can ignore it twice, as it is so obviously self-serving.
Anyway, as I said I rather leave it as it is. Obviously asking the guys who were killing themselves out there right after the match would produce only one answer (specially the guy who lost).
It also does not matter one bit if it hurts the players. A competition is made to "hurt" the players: you do not win, you're out. You cannot win it quicker, you're dead in the next one. It is as simple as that.
As for to who does it serve, it is quite obvious to me: it serves everyone. The unpredictability of the outcome, of the timing, the fact that it shakes the so boringly square structure of everything... you really need to look at it from a bigger perspective. Every match that gets to 4 all in the fifth becomes tense and grabs attention, because, among other things of course, it may become a marathon. And still most of those matches end up at 6-4 or 7-5. But the public enjoyed it, people turned their streams on, commentators talked about the match and so on. Then some match goes 8-6. Oh, what a classic! The occasional marathon is a small price to pay for everything you have in return.
And in the marathon we get to see two guys killing themselves out there. Sports, after all, are just about that. Would you trade that moment were Anderson fell, got up, used his left hand with a strange grip to finally win the crucial point, at 28374625 all, for a mere fifth set tie-breaker? I wouldn't.