Some interesting numbers were calculated by the statszone. The run rate per over in test matches has gone up since 1986 from around 2 3/4 per over to about 3 1/4. The upturn was a bit sudden, around the millennium. I'll keep looking. It would possibly be rash just to "blame" limited-overs cricket. Arguably, pitch prep might have slightly favoured batsmen. Remember how those drying wickets favoured spinners? Well these days they dash out with the covers at the first hint of rain. A lot of wickets look like dustbowls these days. They might favour bowlers more towards the end of the match when the pitch has broken up a bit, I suppose.