I haven't planned out anything. I haven't mapped out anything. I'm going to build whatever feels right at the moment...and then, as I play the game, I'm probably going to discover that I spent things in one area that I had rather spent in another. Then, I'll figure out how to respec - and I'll do that.
I understand you're looking for advice on how to build your character for the future, but, honestly, if you ask me (and you kinda did, given the nature of your post), I might personally suggest not worrying so much about the end. As far as I've heard, re-speccing is going to be available in the game, and you can't *really* know how things are going to work until you actually play the game, and so the best info you're going to get about what you want IN the game, is going to come from playing it - there is ABSOLUTELY NO SUBSTITUTE for personal, first-hand experience.
Don't get me wrong - it's a good question. People who've done this before, or have thought about it before, can give you things to look out for during your own experience that will help you focus your perception - so it's a good question. I'm just advising that you don't get overly married to ANY particular build, until you play through the game yourself first. Take all this good advice, and use it to keep an eye out for particular ideas and options during your first character build. Hopefully, when you reach the end of your solo-play adventure in ESO, you'll find yourself wiser, better informed and better prepared than you were when you started, and you'll head to that re-spec trainer (or whatever it is), and spend a load of in-game money to finally tweak all those things you'd been testing out during your initial run through.
then, you can play and enjoy your near-perfect character...until they patch, nerf a buncha stuff, and you have to totally re-learn your character all over again.
welcome to MMOs!