That's a very dangerous perception to have. A lot of this it's a lot harder game for the bowlers is a whole lot of manure. I wouldn't dare call a good modern day batsmen average.
I think, batting has changed more than anything else. I think, a lot of emphasis is now laid on mindsets. I've noticed an unbelievable change in the outlook of the modern day cricketer. He just doesn't believe in the word impossible. It's like the moment you dangle that carrot, a group of young cricketers see that as an opportunity to shine and not worry about failure. If you just see the scoring areas now, it's unreal in the 90's. I just feel the bowler hasn't evolved as much as the batsman has.
Just to sight out a few things I've heard people mourn about, specially commentators-
Pitches are dead dodo's, they are docile and flat. This isn't true. I think, all the pitches mostly keep their true nature. We've had more results in tests than forever. Yes, there's the odd drop in pitch sometimes that's dull, but there were more 'draws' in yesteryear than there are today. I frankly, love ODI cricket now. If you have a weakness in the team, you will be stripped naked. The only issue I have sometimes is that the boundary is in, which was not the case at the world cup so it was fine. The only rule that needs changing is the fielding restrictions. McCullum will still have fielders in. de Villiers will still hit sixes. Starc will still pick wickets. You just allow a bit more captaincy to come in as well as reward the bowler for accuracy.
There's a lot of nostalgia and romance about the past. Why? Because you can't travel in time. Understandably, a lot of cricketers are termed as legends and rightly so. But, we sometimes under estimate how brilliant the present is. One day, this will be the past and people will remember some of these chaps as legends and miss them. eg. When you talk of legendary fast bowlers, we always hear Malcolm Marshall and Wasim Akram. Yet, when you talk of greats in terms of batsmen everyone in the present is said to have these drop in pitches, flat tracks, BIG BATS etc. etc. Well, if batting is so easy in today's day and age compared to yesteryear, every time all time great bowlers are discussed, Steyn and Anderson should be discussed a lot before Hadlee, Marshall etc etc.
ps: Nothing against your post or you. Just wanted to share myths. Very dangerous to compare eras in sport. Each is unique. And so, we will never know who is average in yesteryear or special.