I'll like to clear some things before we move on.
First a level 5 adventurer has the physical stats of a level 50 player and so on, bit please keep in mind that a level 50 player will crush a level 5 adventurer because of the various profession skills and resistance they posses.
Of course Lioro cannot be simply compared as such since he has multiple special classes and even an Epic class which didn't exist in yggdrasil.
Second Spells like skeleton dragon series are great against mages because their high magic resistance, BUT they don't have any physical resistance meaning they are weak against fighters.
Third, Epic classes have a conditon when they are being acquired, Lioro was able to get divine Smith because he saw the whole process of Hephaestus making a true divine weapon from the start to the end, note that a random weapon made by Hephaestus would not have satisfied the condition, Hestia sword is a peak weapon which can grow, it met the minimum standard for acquiring the class.
Fourth, Lioro cannot copy racial skills or Inborn talents.
Fifth, When Lioro reaches the max level of a class, it doesn't mean he has the same stats as the original holder.
What does that mean?
Look at it like this, he has an intermediate class Adventurer which he received from Hestia's blessing, now if he levels it up to like lv 5 then that doesn't mean he has the same stats as a lvl 5 adventurer, for that he needs like total level 50.
Similarly having lv 3 in Epic class doesn't mean he becomes as powerful as a god, he gets thair skills but not their attributes.
Fifth, if you dont give power stones and reviews then story might get droppeed.... :)
Since you guyes have read till now, I believe you should understand the whole system and everything, still if you have any questions then I will try and answer them here. No future prediction only answering any doubt you might have on prev chapters.