As mentioned, too much been swung in favour of batsmen now - better pitches/outfields, one bouncer per over and the emergence and encourgement of T20 cricket. There are far more "dashers", as I'd call them - lads who can go out and whack a quick 100 on a good pitch and look like a world beater, in replacement of an anchorman, someone like a Boycott/Lawry/Viswannath who would look to bat all day. The point I would make is that those 3 could play in any era with their style and be effective, how many of these so called top batsmen now could have batted the way they do now, on uncovered pitches against Lillee and Holding for example, 30/40 years ago? - not many I bet.
Real destructive batsmen batsmen of today's era like Sehwag were around before, look at Greenidge/Haynes/Fredericks but the majority of batsmen are certainly flattered by poor bowling attacks and featherbed wickets. Ian Bell and Kevin Pietersen average nigh on 50 in test cricket, yet one can't hit a quality spinner off the square and the other goes to pieces at the sight of a left-arm spinner. Top quality batsmen these days will be decided by longevity and something that is often forgotten in the face of a packed international calender - match winning innings made under pressure. Players such as Dravid, Kallis, Tendulkar, Ponting, Jayawardene have the technique and mental strength to score runs in all conditions, I'm not sure some of the so-called "best around" are quite as consistent, flat track bullies some would say where years ago, very rarely did you not have to work hard for your runs. Now, with bigger bats, quicker outfields, shorter boundaries and authorities preparing batting pitches to last 5 days for financial gain, scoring runs almost looks too easy, but you can tell the class apart, as they will make it look easy on a cloudy day at Headingley, or a raging bunsen burner in Colombo.
