Wait so I'm confused and some probably rather dumb questions.
If you level a job, say DoW and you get pretty high level, but then decide you want to go level a DoM, you will be level 1 right (I'm confused because of the whole "physical thing")? I read somewhere (can't remember where sorry) that you'd be able to reset your skills you'd chosen in case of situations like this. And, if you can reset your skills (like strength, dexterity, mind etc) wouldn't it be a pain to switch your skills each time you switched between two different classes, like a high level DoW to a high level DoM? How will this work??
You have a physical level which is the same regardless of your current class, and that determines your HP and MP, as well as providing stat points and resists that you can allocate.
Then you also have a class specific level (or "skill" if you prefer). That determines which abilities are available to you, both from your current class and skills that you can equip from secondary skills.
To switch between classes you can just swap weapons and voila you are a new class.
To change stats and resists, there is a "re allocate" button that you can just press whenever you want to get all of your stats refunded. Then, you just click on the new stats to allocate. As long as you have a general idea how you want to allocate your stats it shouldn't take more than a minute to do. Obviously the higher your physical level the longer it will take, but we're talking about clicking a button, not filling out a survey, so it shouldn't take longer than, for example, creating a basic macro in FFXI takes.
And also, talking about healers, if you choose a DoM class I've read people saying you can just focus on the healing aspects if that's what you want to do. Is that implying that you'll be able to choose branching paths in that job (since no specific job seems to be purely healer)? Kind of like in WoW where you're a certain job and as you level you get to choose between branching paths? Or is it more where you'd just be using the healing abilities and ignoring the other magic abilities you have? This is very curious to me because I didn't like enfeebling and stuff, and you always get in parties as a mage of any type where someone demands you play the mage a certain specific way.
From what I understand, you unlock all abilities of your class as you level it. However, you can only have a limited number of abilities enabled at any time, so while you might have 50 different abilities at level 50, you might only be able to equip 20 of them. The more classes you've levelled up, the more abilities you'll have that are going unused.
As far as healing goes, it looks like you can choose to have a dedicated healer if you want (and if you're fighting really tough mobs in a group you probably will want to) but there are a ton of ways to get healing, including being in the non combat stance (slow HP regen), using self healing abilities that most classes possess, using battle regiments (similar to weapon skills in FFXI but with many more possible effects than just damage),consumables such as potions, or having every one in the group enable at least one healing spell that they can toss around as needed. The game is meant to be playable solo, duo, trio all the way up to 18 people in a group, so there's an enormous amount of flexibility. How you handle healing in a group will probably depend a lot on what you're doing and what size group you have, but there are a lot of options that we know about already and probably some that we don't.