You do know you could always do that?
It wasn't encouraged, and wasn't as easy as it looks like ti will be in Sky.
Except thats not what he says
The nearest to that he says is, "you want to play like a battlemage you just do it, you don't have to pick some character in the beginning" which does not IMO mean what you suggest
Its not just that statement, its pretty much every design decision around character creation.
That makes sense, in the beginning. It comes down to how you play, if you wanted to play a battlemage from the start and played towards it then you would end up a good battlemage. If you played a warrior for say 20 levels putting attributes into health and stamina and didn't touch magic, then you just went 'screw it I'll be a battlemage' then your going to have to spend your next few attribute points into magicka to be able to use spells reliably and you'll have to level magic and decide if you want to spend perks, and by doing so reducing your potential if you went pure combat. So it's not like it won't have consequences, just depends how far on with your character you are.
If you got to the 40's playing as a stealth/magic hybrid and decided you want to go full out warrior then... you can't really, it's too late. One of the main things I love about this new system is characters will have real weaknesses even at the end of the game, unlike Oblivion where it was possible to max everything with a bit of effort.
If your switching up over practicality, and not becasue of an RP, then I dont think Beth should appeal to you. Basically, people playing like an RPG, VS people that play like an action game.