^ For those reason its hard for me to compare and rate SRT, Lara, Ponting higher than batsmen of 70s,80s, rules were relaxed a whole lot for them...Plus 4 fearsome bowlers, we have hardly seen any batsmen succeed against full blown WI in a series, that kind of test is not possible again after 1980s, it may never happen(simply rules and quality of that many bowlers in a team is hard to replicate)
Similarly, now flat pitches (thanks to global warming, T20 and whole lot of other reasons) and batsmen with no threat of bumpers cannot be compare, their averages will be higher... Good bowlers are not going to play test cricket in near future (if they are not already), again too many parameters that effect the cross era comparison...