I certainly hope there is a hard cap on stats (the 500 points you get at character creation), otherwise we will have shades of Darkfall II here.
If stat increases mean that points are added in addition to the starting 500, then whoever grinds/macros/plays the hardest and longest will have a huge advantage over everyone else after a few months. What happened in Darkfall shows the danger of that system. It leads to a massive temptation to macro, just to stay "competitive", let alone getting an advantage.
A hard cap forces you to choose, it means that not every player can do everything equally well. The skills are tied to certain stats, so the skills you use most often should generally increase their related stats. Points for those stat increases will be drawn from the stats that you don't use, so you get better at what you LIKE doing, and worse at what you DON'T like doing. No real problem there.
There may well be no cap on SKILL points, but we have yet to see how useful it is to have low primary stats for a skill that is at 90 or 100. For instance, high Fortitude and Agility determines your run speed, but the Running skill reduces the energy used while running. So the Running skill does NOT make you faster, it just allows you to run further. We have a lot to learn about the relations between stats and skills.
Again, this is just my understanding of how things work in Xsyon. I could be totally wrong, but I hope not.