We can do a bit of a test on this if some people here are willing to spend a few career mode innings playing nothing but defensive shots to see how long they can hold out for.
A recognised batsman should find a pure defensive stroke reasonably straightforward and low risk. If you nick off then it's either a really good delivery with late movement or you've badly messed up the shot.
I've already tried it, prior to removing the patch.
What I found when defending is that instead of getting out for 10 - 30, I got out for 0.
Most often to fullish deliveries, heading down legside, that I either edged onto the stumps - or over and to the keeper.
I've actually got another "testing" career, where although it's a brand new career, the player is 26. I might try a "defend everything except stuff you can leave" approach there, see how long it is before I get out.
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A few people have said this and I'm a bit puzzled as to why they're not having a problem. It's invariably going in the air to the inner ring for me just like the other shots, and gkrama's video above shows a leg glance like that.
Heh - I think for me it's a case of the leg glance being better post patch 2, rather than fine.
Without the patch, I found it literally impossible to keep it on the ground. With the patch I can keep it down if it's full enough ...
*edit* @
HBK619: just came out of the nets, batting with my career guy against an off-spinning machine. I noticed that there's no appreciable difference (in the nets, at least) between ideal and late timing as far as the results of the shot go. Seems just as likely to get an edge off either ideal or late, and both ideal and late shots go aerially.