I'm going to start off by saying I am in favor of having a group grinding system in place. I was an avid XI player and loved exp groups (a major reason is probably because I had a static group of friends and didn't have to sit in Jueno for hours waiting) because they did take skill into account. My main was BLM that I lvl capped in the time when sky was new and actually used as valid content.

The idea that everything you fight to level in group gameplay can kill you very fast if someone screwed up is amazing and that is the idea they need to keep in group grinding, imo. XI ruined it when they allowed TP burn parties to continue because it made leveling faceroll status where everyone did whatever the hell they wanted to an imp and watched it die before the entire group could even reach the mob.

If they make group grinding like it was when teamwork was an essential aspect of the game that taught people how end game mechanics worked, then I think it would make for a more enjoyable game for everyone since new people won't be as inexperienced at the lvl cap as say... fresh 80s were in WoW.

Also, they need to keep a level of competition in grinding parties like they had in XI. There was always that one "sweet" camp everyone wanted to level at but could only sustain one group at a time. Then people had to move on to other camps that could handle more groups but had less favorable conditions. It made it so people weren't just killing monsters hour after hour, weapon skill after weapon skill. Sometimes you had to have multiple pullers, or even your entire group, going after the spawns to ensure that another group wouldn't successfully muscle you out of your camp.