If a user wants to have default formatting like you suggest then they need to set their setting in the Settings tab to BBCode. They can then place whatever BBCode they want.
I'll use your example as my example.
In your profile you do this for your default BBCode.
[font face="arial" size="2" color="4e1900"]
[/font]
When you go to post it loads in BBCode mode and you see this.
[font face="arial" size="2" color="4e1900"]
[/font]
You have to
click onto the second line in between the tags and start typing.
If it loaded you default BBCode in the Visual Editor it would look like this.
Where do you click? How do you click between the tags? You can't, because you can't see them. In fact I can garuntee you will always click outside of them because they have been pushed together invisibly in the background.
IF you members want to do custom coloring, sizing and fonts then they do need to learn BBCode. That's not asking more than v4 did. In fact they don't even technically have to learn anything. They can go into a posting page and use the visual editor to style a bunch of text. Then they can click into BBCode mode and simply copy and paste the tags they see there. Then they can go paste those into their Settings page of their Edit Profile.
There is no way for the Visual Editor to store anything, because it is still using the BBCode, it's just in the background. That's why you can toggle between them.
The Visual mode is the equivalent of the Preview in v4, except you can actually edit while you preview. Your members should all be used to the v4 way of using BBCode already.
So they have to choose. They can either use BBCode and store it or just use the forums default or manually style each of their posts every time.
Don't forget to remind them that they can switch between BBCode and Visual mode back and forth, back and forth just by clicking the tabs below where they are posting. So they can store default styles and then swap to Visual mode when they need it. They're either using default styles they saved or they are customizing new styles. If they want to do both every single post then it requires them to click one extra time. That's not asking a lot considering how much styling they must be doing. It's really simple.
I hope that explains it.
Edit: What I bolded above is really the key to this. Remember that BBCode is still how all posts are stored and rendered. The visual editor is simply a tool for previewing those changes, and in v5 you can edit that preview live. At the end of the day you still have to save your styles in BBCode, just like v4.
I do understand what you are saying. However, in V4, when someone replied to a post, it brought up the quoted post with the BBCode tags of the quoted user and the responding user just typed what they wanted. When they clicked to post, the BBCodes fonts that had selected in the profile then bracketed what they had just typed. Therefore, the user had their desired selected font every time without needing to learn codes and placement. In V5, the code is automatically inserted after the quoted text and BBCode. So the user has to know where to place their text. Easy for a techie, not so easy for average users.
I guess I was wondering if there was a reason why it changed, making use a bit more difficult for users.