As of next season, bowlers will be permitted to bowl ten overs maximum instead of current nine. However, no more than 45 overs total are to be bowled by any set of five bowlers - ie. your sixth bowler combination still needs to bowl five. For example, you could have this: Bowler A: 10 overs Bowler B: 10 overs Bowler C: 10 overs Bowler D: 10 overs Bowler E: 5 overs Bowler F: 5 overs Or this: Bowler A: 10 overs Bowler B: 10 overs Bowler C: 10 overs Bowler D: 9 overs Bowler E: 6 overs Bowler F: 5 overs Or this: Bowler A: 10 overs Bowler B: 10 overs Bowler C: 10 overs Bowler D: 10 overs Bowler E: 5 overs Bowler F: 3 overs Bowler G: 2 overs Or this: Bowler A: 9 overs Bowler B: 9 overs Bowler C: 9 overs Bowler D: 9 overs Bowler E: 9 overs Bowler F: 5 overs Or this: Bowler A: 10 overs Bowler B: 8 overs Bowler C: 8 overs Bowler D: 8 overs Bowler E: 8 overs Bowler F: 8 overs etc etc. Basically, the five bowlers who bowl the most overs can only bowl 45 between them, maximum.
We have a lot of allrounders in CricSim, they become less useful if you let teams just pick five bowlers and we'd end up with too many of them in reserve grade.
I actually flirted with the idea of having 60 overs games with 10 overs per bowler and allowing the 12th man to bowl (just to get more people involved basically), but it was too unlike real-life OD cricket so I scrapped the idea.