I'm loving the game so far, but this is a massive downgrade from Sm4sh. Lumping everyone in together, and having every battle affect your GSP ranking in unpredictable ways is stupid. No matter what you actually want to play, it throws you into a random match likely completely different to what you wanted. I just spent 10 matches working my GSP up over 600k with Isabelle, only for a single loss to item spam to slam my ranking back down to 275k. In the next match, I got thrown into a team battle with some random against two players who were obviously working together and got double teamed to hell (the other guy got taken out in ~40 seconds, leaving me alone), and though I took them both down to a single stock left each, my ranking crashed to 90,000. Complete shit, and completely drained my motivation to touch online again.
Both For Fun and For Glory had their own place and were good times in their own right, why not at least keep them separate and give them different rankings or something? Lumping everything together just ruins the experience