It is, as has been pointed out, ridiculous to assess a player whose career ended nearly 60 years ago. There are a whole lot of variables within the game of cricket which have been altered since those seemingly idyllic, almost romantic days. If Donald Bradman played today, this is what I think will be in his favour:
- No sticky wickets
- Flatter pitches
- Better bats
- Smaller boundaries
- Better protective gear (and no Bodyline, to boot)
...plus the fact that he was still dominating net bowlers as a 68-year old.
This is what I think will go against him:
- Timeless Tests (I'm almost certain that they featured in his era; I'm not sure whether he ever had the opportunity to play one)
- Better ground fielding
- Greater professionalism of bowlers (leading to a greater amount of desperation, as a lucrative career is on the line)
- More media pressure (I don't know how he'd react if the media - and by extension, people who read various media - wrote him off after a few relative failures because of his exceedingly high standards)
- More substantial video analysis (allows bowlers to probe for technical flaws, although his supreme discipline would reduce the effect of this - see Justin Langer)
He would probably cope just as well as he did back in the 1930's, but it is impossible to say for sure, so I'm wimping out on this one.