This is why I was very picky about making a ton of Miis. I'm leaving a lot of room. I expect like PSO I'll max it out by the end. When I played PSO I maxed out my friends list towards the last few months.
On my PSO friends list is the legendary Virus UD. The best Mario Kart player on the planet. At least he was on X-band. I was lucky to bump into him on my last month of PSO for the Dreamcast before they closed the servers. Always leave room in case you bump into those legendary players.