Finally going to give my 2 cents. And we all know what that is worth.......
I think I would prefer 7 rounds, but in all reality it doesn't matter. I get to shot my 1911. I will say the 5 in a mag has been a challenge shooting IDPA, but that is my challenge. Remembering that I don't have to hit the slide release because I have one in the chamber, the magazines seat harder with 7 or 8 rounds in them and I still use no base pads or mag wells in IDPA. But these are my decisions.
We recently participated in a 2 day defensive pistol class. Actually a great class. There was an IDPA shooter and match director in the class and we got to rag on each other during the class. First he hit me with the dress. I countered that the dress shouldn't be a factor as jeans and a long sleeve shirt were fine along with boots. But I countered again that in IDPA we have to wear a cover garment or as he and many wear a "Shoot me first vest" so that shut him up. Then came the loading of 5 in the magazine. I looked at him and asked; How many rounds does that XDM hold? He replied 17 and I followed up with "What is the max can you load in IDPA? 10 rounds. I looked at him and didn't have to say a word. The light went on ... wow and you could see him process that we have restrictions as well.
While 5 rounds is what it is, most shooting sports have rules and we all have to play within those rules. I really think the need to purchase a rifle and shotgun and use lead bullets are in my opinion the largest drawback not the 5 rounds limits in the magazine. Not everyone reloads and the majority of shooters in other sports shoot 9 mm or 40. They will use whatever excuse is convenient at the time.