Coaching has certainly improved, both in terms of the level of knowledge specific to the coaching of the game (as opposed to the playing of it) which exists, and in terms of the tools available to assist coaches in doing the best job possible.
But...
...I'm far from convinced that that phenomenon is responsible for the perceived difference in how well batsman play "pace" bowling. If we benchmark 1986 and 2011, so 25 years apart, there are a number of factors which have made it much easier for batsmen to prosper against the fastest bowling:
1. The standard of pitches - even accepting that they were covered by 1986, pitches worldwide were considerably more helpful to quick bowlers than they are now. Think about it - Perth aside, where in the world does one now regularly see fast, bouncy wickets for Test cricket? Part of this is based on the needs of administrators for the game to last as near as possible five days, but drop in pitches (NZ), a lack of investment in infrastructure (the West Indies) and changes to individual grounds (Old Trafford, Headingley, The Oval) have made pitches bland.
2. The amount of cricket played - allied to the modern obsession with non specific fitness, as opposed to match fitness, this means that the fastest bowlers spend an inordinate amount of time benched.
3. Bigger bats lighter pressed equals easier runs for batsman against all bowling, fast or slow.
Of course, the biggest difference really is the lesser standard of fast bowling in the game - in the easrlier timeframe, the West Indies alone could field Marshall, Garner, Ambrose, Walsh, the Benjamins, Syl Clarke, Wayne Daniel etc, whilst Pakistan had Imran, Wasim etc and the Kiwis Hadlee. There isn;t that much around of a comparable class today!