i think all new stadiums need atleast a retractable roof. Im not a fan of the pure domes, such as Minnesota and Toronto. But i think the retractable ones should be mandatory to all teams creating new ballparks. This makeup games can really affect how a team plays and could contribute to a team not making the playoffs. Say a team at the begining of the season, gets off to a hot start, say 16-4 and a 5 game winning streak. Then their next 2 games get rained out and they have to make them up in June. June comes along and the teams struggling, winning 2 of their last 12. They lose the 2 games and end up not making the playoffs by 1 game. Rainouts are also a pain to re-schedule and screws up pitching matchups.
I hate rain outs!!