I'm a football - baseball guy also...
If the season went through Feb,I'd be fine with it as I like to watch the cold snowy games on T.V.,and generally I'm pretty bored with what is one T.V.....Starting earlier,I don't really know,perhaps 1 week earlier at most.Living in the midwest,I'm still in Camping/floating do outdoors stuff into October,before it gets too cold and I've got to prepare for winter.
I see the owners,especially in the northern Climates,would more strongly object to longer season for 2 reasons off the top of my head..
1.) Perhaps less people go to the game,with bad roads....
2.) Possible less beer sales in those colder games Jan-Feb games...
I imagine there are more real reasons I just can't think of at the moment...