[Crenshinibon]

The power of dual class versus multi-class characters can be argued, so we'll say that it lies with whatever choice you favor, though certain combinations, such as the ranger/cleric, are more powerful in multiclass form.

The abilities lost due to dualling come back as soon as your second class surpasses your first class in level.

So for example, you dual from a Kensai to a Mage at level nine. This causes you to lose Kai as well as all your proficiencies. As a mage, you can put proficiency points in the available weapons, such as dagger or sling, and they will carry over when you hit ten, though keep the restrictions in mind as in even if you have a point in slings, you won't be able to use it after your Kensai abilities are restored as the first class cannot use missile weapons.

Also, let's say that your Kensai had two points in daggers, as a mage you put one more point in daggers too. When your first class is usable again, you will have a total of three points in daggers, so the proficiencies stack, letting you get more proficiencies than any other multiclass or rivaling them. So a thief/mage would be able to get two in common weapons while a swashbuckler cleric would get three in common weapons. For thieves, you once you get Use Any Item, the proficiency from the previous class will apply to the weapon you're using.

For me, if I solo or even have up to two NPC is my group, I can recover my second class by the time I finish Chapter 3 and that's if I dual at twenty one or higher.

I think dual class characters are more for due to the extra abilities you get as well as being able to do the things you couldn't before.

I mean a fighter/druid is just weak compared to it's dual class counterpart, the kensai/druid who can reach the same AC while dual wielding two scimitars.