Why does baseball have to keep changing?

I have not, for one minute, understood why there is even discussion about moving another team to the American League. I also don't understand how there can be a connection between that move and more teams added for postseason play. Baseball has decided that there should be an equal amount of teams in each league and division. This is the same sport that decided to add two expansion teams for the 1998 season and make sure one of them was in each league. And on top of it, moved a random American League team to the NL to give the leagues an uneven balance. Now we all understand why that was done. In 1993, the NL got the Marlins and Rockies to even up the amount of teams in each league to 14. And when there's an even number of teams in each league, teams can play games within their own leagues each day. So, when they decided on expansion again for the 1998 season, the AL was upset that the NL was getting two teams and they were getting none. So, thats when the Brewers joined the NL. So after all these years, we want the same amount of teams in each league. And now its totally ok if there are interleague games every day of the season. But, once again, what does that have to do with adding postseason teams? 
So, if an NL team is switching leagues, why does it have to be the Houston Astros, a team that has been in the National League since 1962. It seems like baseball is now turning against its own history. I mean, they already moved the Milwaukee Brewers to the NL before 1998 after being an AL team since 1969. Why can't they just go back to the league that they started in? They are a midwest team an can play in the AL West. How about Colorado or Arizona, two western regional teams who have only been in existence since 1993 and 1998, respectively?  
Baseball should just try to stay the same way it has been. Its not like they are trying to recruit new fans. Changing the game any more is not going to draw more people. We've gone through expansion, 162 game seasons, the designated hitter, interleague games, the now twice expanded postseason and now randomly switching teams between leagues and playing interleague games every day. And I suppose these are the same people who robots as umpires just so every call can be right, every time. I say just leave the game alone and keep the history as consistent as it could be.