It was far FAR from a bad Mario sports game, but it did have some flaws, the main one that I remember is fielding but overall it was a solid and fun game. Perhaps nothing amazing but it was fun.
Hell this is probably my favorite Mario sports game. The fielding was manageable and just took a little getting used to, but after that I never had any problems. It was arcadey and fun and it had a nice balance of characters to build your team out.
The summer that it came out I bought it for full retail price (which I don't usually do for a Mario Sports game) and literally played it the entire summer exclusively.
I'm somewhat interested in this iteration, but it doesn't seem different enough for me to get excited.