Having a strong combat character is both useful in that you can heavily influence the outcome of a battle and generally makes the game more fun. Strength and agility are more of a toss up. You will need to have a big army in this game and that requires persuasion to build and leadership to maintain. You don't need an absurdly high charisma to be successful but having a reasonable amount will greatly improve your quality of life. The most important attribute in VC is charisma.
As such I recommend using this guide to optimize your character. This means that your starting attributes matter much more than they do in Native while your starting skills won't make any difference past a certain level. You will also gain two skill points per level instead of the single point you would receive in Native. Secondly, you can raise a skill up to half of the value of the relevant attribute rather than the one-third in Native. You get your first point at level 6 and will get an additional point at levels 11, 16, 21, and so on. Firstly, while your starting attributes are much higher, you only gain a new attribute point every five levels. In a general sense, character creation in VC follows the same general rules in Native. I'm assuming that anyone playing VC already has a basic knowledge of Native. This is a Guide to the Mount & Blade Viking Conquest (VC) mod.