There is no increased stam drain on low HP like it was in MO1 and this seems to be a big issue when it comes to the drawn out kiting.
Magic and mounted is much easier to balance to the foot combat system than the other way around. With the slower movement speed, combat now have a feeling of range. Ranged weapons like bows and magic might be able to get more damage done, before you reach them. Depends on if you even get enough time to cast one more spell or shoot another arrow.
Mounted are as always having speed advantage on foot so if your solo on foot or to spread out you will get easily picked off by mounted. If you form a circle with shields/spears you can easily hold of mounteds and take very minor damage. This was the case in MO1 even before the nerfs and when EQ didnt dismount and hit for 80s(got nerfed to 60s). Assuming there wont be anymore changes to mounted players in MO2, it will be somewhat similar. Mounteds might need some buffing to be honest. They got so many nerfs after the EQ change. They where however still viable in their intended areas of combat, but had to increase gear cost to easily dismount other mounteds. I cant speak of how elementalism changed mounted as i have barely seen it in use.
So to sum this up i think there will not be any massive difference in the combat from how it was in MO1, but that players will be stay together more and a lot due to the foot movement speed being lowered and map being bigger(more important to stay alive). I would expect mounted would get a similar movement speed decrease as it makes the game look and feel better, less teleporting. I would like to see mounted and magic how it looks and feels and if it got bugs that needs fixing, but i dont think it will change much in combat balance.
Never meant to type this much... Sorry.